Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB))

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MeerKAT view of Hickson Compact Groups. I. Data description and release
(EDP Sciences, 2025-04) Bosma, A.; Athanassoula, E.; Józsa, G.I.G.; Jarrett, T.H.; Xu, C.K.; Román, J.; Labadie, X.; Cabanillas de la Casa, C.; Borthakur, S.; Wang, J.; García-Benito, R.; del Olmo, A.; Perea, J.D.; Wiegert, T.; Yun, M.; Ianjamasimanana, R.; Verdes-Montenegro, L.; Sorgho, A.; Hess, K.M.; Jones, M.G.; Cannon, J.M.; Solanes, José M. (José María); Cluver, M.E.; Moldón, J.; Namumba ,B.; Garrido, J.; Sánchez-Expósito, S.
Abstract Context. Hickson Compact Groups (HCGs) are dense gravitationally bound collections of four to ten galaxies and are ideal for studying gas and star formation quenching processes. Aims. We aim to understand the transition of HCGs from possessing complex H I tidal structures (so-called phase 2 groups) to a phase where galaxies have lost most or all of their H I (phase 3). We also seek to detect diffuse H I gas that was previously missed by the Very Large Array (VLA). Methods. We observed three phase 2 and three phase 3 HCGs with MeerKAT and reduced the data using the Containerized Automated Radio Astronomy Calibration (CARACal) pipeline. We produced data cubes, moment maps, and integrated spectra, and we compared our findings with previous VLA and Green Bank Telescope observations. Results. Compared with previous VLA observations, MeerKAT reveals much more extended tidal features in phase 2 and some new high surface brightness features in phase 3 groups. However, no diffuse H I component was found in phase 3 groups. We also detected many surrounding galaxies for both phase 2 and phase 3 groups, most of which are normal disc galaxies. Conclusions. The difference between phase 2 and phase 3 groups is still substantial, supporting the previous finding that the transition between the two phases must be abrupt.
Fully comprehensive diagnostic of galaxy activity using principal componentsof visible spectra: implementation on nearby S0s
(Royal Astronomical Society, 2025-02) Tous Mayol, Josep Lluís; Solanes, José M. (José María); Perea Duarte, Jaime D.
We introduce a novel galaxy classification methodology based on the visible spectra of a sample of over 68 000 nearby (z≤0.1) Sloan Digital Sky Survey lenticular (S0) galaxies. Unlike traditional diagnostic diagrams, which rely on a limited set of emission lines and class dividers to identify ionizing sources, our approach provides a comprehensive framework for characterizing galaxies regardless of their activity level. By projecting galaxies into the 2D latent space defined by the first three principal components (PCs) of their entire visible spectra, our method remains robust even when data from individual emission lines are missing. We employ Gaussian kernel density estimates of the classical Baldwin-Phillips-Terlevich (BPT) activity classes in the new classification subspace, adjusted according to their relative abundance in our S0 sample, to generate probability maps for star-forming, Seyfert, composite, and low-ionization nuclear emission-line region (LINER) galaxies. These maps closely mirror the canonical distribution of BPT classes shown by the entire galaxy population, demonstrating that our PC-based taxonomy effectively predicts the dominant ionizing mechanisms through a probabilistic approach that provides a realistic reflection of galaxy activity and allows for refined class membership. Our analysis further reveals that flux-limited BPT-like diagrams are inherently biased against composite and star-forming galaxies due to their weaker [O III] emission. Besides, it suggests that although most low-activity galaxies excluded from these diagnostics exhibit visual spectra with LINER-like characteristics, their remaining activity is likely driven by mechanisms unrelated to either star formation or supermassive black hole accretion. A machine-readable catalogue listing BPT-class probabilities for the galaxies analysed is publicly released with this article.
Growth of Ex-situ Diffuse Intergalactic Light in Simulated Galaxy Groups
(EDP Sciences, 2025-03) Bilata-Woldeyes, Betelehem; Perea Duarte, Jaime D.; Solanes, José M. (José María)
Context. Deep surface photometry has revealed the presence of a faint and diffuse baryonic component permeating the intragroup space in a significant fraction of galaxy groups. This intragroup light (IGL) is primarily formed by stars that are removed from their host galaxies through gravitational interactions and now drift freely, unbound to any particular galaxy. Aims. We conducted a detailed analysis to investigate how various physical parameters of galaxy groups influence the formation of ex situ IGL during the earliest stages of group assembly, and to explore their correlations with the mass and fractional abundance of this component. Additionally, we evaluated the potential of the IGL as a luminous tracer of the total mass distribution in galaxy groups, with a particular focus on systems that are far from dynamically relaxed. Methods. We used controlled numerical simulations of 100 low-mass galaxy groups spanning a range of masses and numbers of constituent galaxies to track the formation and evolution of IGL during the earliest pre-virialization stages of these systems. Results. We show that the IGL typically begins to form in significant amounts after the turnaround epoch, which in our simulated groups occurs at a median redshift (z̄_ta) of ∼0.85, increasing steadily thereafter. We observe a sub-linear relationship between the masses of this component and the brightest group galaxy, which indicates intertwined formation histories but differing growth rates. This suggests that other group members may also significantly contribute to the diffuse light. Additionally, we observe indications that IGL formation is enhanced in groups with lower internal velocity dispersions, which suggests that gravitational interactions between member galaxies become more efficient when their relative velocities are reduced. For two-thirds of our groups, the radial surface density profiles of the total and IGL mass are significantly aligned, with fractional discrepancies below 25%. This supports the notion that this diffuse and faint baryonic component serves as a reliable tracer of the total gravitational potential in galaxy aggregations, regardless of their dynamical state. However, the results also indicate that the degree of similarity depends on the viewing direction.
MeerKAT view of Hickson Compact Groups. II. Deficiency in the core andsurrounding regions
(EDP Sciences, 2025-04-18) Jarrett, T.H.; Namumba, B.; Pérez, E.; Román, J.; Smirnov, O.; Yun, M.; Cannon, J.M.; Bosma, A.; Athanassoula, E.; del Olmo, A.; Perea, J.D.; Moldón, J.; Wiegert, T.; Sánchez-Expósito, S.; Garrido, J.; García-Benito, R.; Sorgho, A.; Verdes-Montenegro, L.; Ianjamasimanana, R.; Hess, K.M.; Jones, M.G.; Korsaga, M.; Wang, J.; Lin, X.; Solanes, José M. (José María); Cluver, M.E.; Józsa, G.I.G.; Borthakur, S.
Abstract Context. Hickson compact groups (HCGs) offer an ideal environment for investigating galaxy transformation as a result of interactions. It has been established that the evolutionary sequence of HCGs is marked by an intermediate stage characterised by a substantial amount of H I in their intragroup medium (IGrM) in the form of tidal tails and bridges (phase 2), rapidly followed by a final stage in which no IGrM gas is found and i which their member galaxies are highly H I deficient (phase 3). Aims. Despite numerous single-dish and interferometric H I studies on the HCGs, a clear H I picture of the groups within their large-scale environment still remains to be uncovered. Taking advantage of MeerKAT’s high column density sensitivity and large field of view, we aim to investigate the rapid transformation of HCGs from the intermediate to late phases, and establish a picture of their gas content variations in the context of their large-scale environments. Methods. We performed MeerKAT observations of six HCGs that were selected to represent the intermediate and late phases of the proposed evolutionary sequence. Combining the H I observations with data from recent wide-field optical surveys, we evaluated the H I deficiencies of galaxies in a ∼30′ radius of the HCGs. Results. We find that galaxies surrounding both phases exhibit similar distributions in their gas content. Similarly, galaxies making up the cores of phase 2 HCGs are comparable to their neighbours in terms of H I deficiencies. However, phase 3 groups are over an order of magnitude more deficient than their surroundings, supporting previous findings that late-phase HCG galaxies are more evolved than their large-scale environments.
The local universe in the era of large surveys. I. Spectral classification of S0 galaxies
(Royal Astronomical Society, 2020-05) Tous Mayol, Josep Lluís; Solanes, José M. (José María); Perea Duarte, Jaime D.
This is the first paper in a series devoted to review the main properties of galaxies designated S0 in the Hubble classification system. Our aim is to gather abundant and, above all, robust information on the most relevant physical parameters of this poorly-understood morphological type and their possible dependence on the environment that could later be used to assess their possible formation channel(s). The adopted approach combines the characterisation of the fundamental features of the optical spectra of 68,043 S0 with heliocentric z≲0.1 with the exploration of a comprehensive set of their global attributes. A principal component analysis is used to reduce the huge number of dimensions of the spectral data to a low-dimensional space facilitating a bias-free machine-learning-based classification of the galaxies. This procedure has revealed that objects bearing the S0 designation consist, despite their similar morphology, of two separate sub-populations with statistically inconsistent physical properties. Compared to the absorption-dominated S0, those with significant nebular emission are, on average, somewhat less massive, more luminous with less concentrated light profiles, have a younger, bluer and metal-poorer stellar component, and avoid high-galaxy-density regions. Noteworthy is the fact that the majority of members of this latter class, which accounts for at least a quarter of the local S0 population, show star formation rates and spectral characteristics entirely similar to those seen in late spirals. Our findings suggest that star-forming S0 might be less rare than hitherto believed and raise the interesting possibility of identifying them with plausible progenitors of their quiescent counterparts.
The local Universe in the era of large surveys. II. Multi-wavelength characterisation of activity in S0 galaxies
(Royal Astronomical Society, 2022-03) Jiménez Palau, Cristina; Solanes, José M. (José María); Perea Duarte, Jaime D.; del Olmo, A.; Tous Mayol, Josep Lluís
This is the second paper in a series using data from about 56,000 S0 galaxies of the local Universe (z < 0.1) retrieved from the NSA catalogue. It builds on the outcomes of the previous work, which introduced a new classification scheme for these objects based on the principal component analysis (PCA) of their optical spectrum and its projections on to the first two eigenvectors (the PC1-PC2 diagram). We provide an exhaustive characterization of the activity of present-day S0s throughout both the broad-band PC1-PC2 and narrow-line BPT/WHAN spectral classifiers, contrasting the different types of activity classes they define, and present an alternative diagram that exploits the concordance between WHAN and PCA demarcations. The analysis is extended to the mid-infrared, radio and X-ray wavelengths by crossmatching our core sample with data from the WISE, FIRST, XMM-Newton, and Chandra surveys. This has allowed us to carry out a thorough comparison of the most important activity diagnostics in the literature over different wavebands, discuss their similarities and differences, and explore the connections between them and with parameters related to star formation and black hole accretion. Among the results obtained, we highlight the finding of evidence that nebular emission from S0-Seyfert and LINER systems that are radio and X-ray emitters is not driven by star birth, while it cannot be discarded that for a number of the members of the latter class the dominant ionising radiation comes from post-AGB stars. These and other outcomes from the present work should be transferable to other morphologies.
The origin of star-forming rings in S0 galaxies
(Institute of Physics (IOP), 2023-01) Tous Mayol, Josep Lluís; Domínguez-Sánchez, H.; Solanes, José M. (José María); Perea Duarte, Jaime D.
Spatially resolved IFS maps in a sample of 532 S0 galaxies from the MaNGA survey have unveiled the existence of inner rings (⟨R⟩∼1Re) betraying ongoing star formation in a number of these objects. Activity gradients averaged over bins of galactocentric radius up to ∼1.5Re have been measured in the subspace defined by the first two principal components of the optical spectra of these galaxies. We find that the gradients sign is closely related to the presence of such rings in the spectral maps, which are specially conspicuous in the equivalent width of the Hα emission line, EW(Hα), with a fractional abundance ¿21-34%¿ notably larger than that inferred from optical images. While the numbers of S0s with positive, negative, and flat activity gradients are comparable, star-forming rings are largely found in objects for which quenching proceeds from the inside-out, in good agreement with predictions from cosmological simulations studying S0 buildup. Assessment of these ringed structures indicates that their frequency increases with the mass of their hosts, that they have shorter lifetimes in galaxies with ongoing star formation, that they may feed on gas from the disks, and that the local environment does not play a relevant role in their formation. We conclude that the presence of inner rings in the EW(Hα) is a common phenomenon in fully formed S0s, possibly associated with annular disk resonances driven by weakly disruptive mergers preferentially involving a relatively massive primary galaxy and a tiny satellite strongly bound to the former.
Tracing the evolution of the brightest galaxies and diffuse light in galaxy groups
(EDP Sciences, 2025-12) Bilata-Woldeyes, Betelehem; Perea Duarte, Jaime D.; Solanes, José M. (José María)
We present the second study based on a suite of 100 cosmologically motivated, controlled N-body simulations designed to advance our understanding of the role of purely gravitational dynamics in the early formation of low-mass galaxy groups (∼1–5 × 1013 M⊙). In this work, we investigate the temporal evolution of key indicators of dynamical relaxation, with a particular emphasis on the secular growth of the diffuse intragroup light (IGL), the four major group galaxies, and the mass distributions of their progenitors. We also assess the diagnostic power of several magnitude gaps between top-ranked galaxies as proxies for dynamical age. As in our previous study, we compare the outcomes from three group classes defined by the number of the brightest group galaxies (BGGs) present at the end of the simulations: single-, double-, and non-BGG systems. We find that the early assembly of galaxy groups is consistent with a stochastic Poisson process at an approximately constant merger rate. Various dynamical diagnostics, including galaxy pairwise separations, velocity dispersions, and the offset of the first-ranked galaxy from the group barycentre, indicate that single-BGG groups evolve more rapidly towards virialisation than double- and (especially) non-BGG systems. We further find that first-ranked group members and the IGL, despite their intertwined origins, follow distinct growth histories, with the IGL assembled from a more numerous and systematically lower mass population than the central object. This distinction is particularly pronounced in non-BGG systems, where about one-third of the IGL originates from small galaxies, each contributing less than 5% to this component. Among the tested magnitude gaps, the difference between the first- and fourth-ranked galaxies, Δℳ4−1, is proven to be a more robust indicator of dynamical age for low-mass groups than the conventional Δℳ2−1 gap. The Δℳ5−1 and Δℳ6−1 gaps also perform well and might be preferable in certain contexts.
The distribution of lenticular galaxies in the phase space of present-day galaxy cluster regions
(EDP Sciences, 2025-05) Gort, Mathias; Tous Mayol, Josep Lluís; Solanes, José M. (José María)
Lenticular (S0) galaxies are ubiquitous in both high- and low-density environments where diverse evolutionary mechanisms operate. Consequently, studying their distribution and properties across both the dense, virialized cluster cores and their sparser surrounding secondary infall regions can provide key insights into the still-debated processes driving their evolution. In this work, we investigated the environmental impact of cluster regions on the evolution of present-day S0 galaxies, focusing on their distinct quiescent and star-forming (SF) subpopulations. We selected a sample of nearby cluster regions by crossmatching optical and X-ray data and extract a subset of 14 systems with maximally relaxed cores by applying strict virialization and substructure tests. A projected phase space (PPS) diagram was then generated from the stack of maximally relaxed clusters up to 3 virial radii to assess the locations of quiescent and SF S0s and their cluster infall histories. Additionally, we compared the radial line-of-sight velocity dispersion (VDLOS) and specific star-formation rate (SSFR) profiles for the different S0 subpopulations, using other Hubble types as benchmarks. Our study shows that quiescent S0s, the dominant class in the entire cluster region, concentrate preferentially at low radii in the PPS diagram, while their SF counterparts are more abundant in the outskirts. Despite this segregation, quiescent and SF S0s exhibit similar VDLOS profiles in the dynamically relaxed cluster core –indicating an advanced stage of dynamical relaxation–, but that resemble those of late-type galaxies beyond the virial radius. This finding, combined with the distinct PPS distributions of both S0 subpopulations, which lead to mean infall times ∼1 Gyr longer for quiescent S0s but that are shorter than those expected for ancient infallers, suggests that a substantial fraction of S0s present in the core region arrive via secondary infall. We also find evidence in the radial SSFR profiles that star formation in S0s begins to decline well beyond the virialized core, likely due to preprocessing in infalling groups. Overall, our results support a delayed-then-rapid quenching scenario for SF S0s in cluster regions, where their centrally concentrated star formation persists for an extended period before abruptly ending (≲0.1 Gyr) after their first pericenter passage.
Characterizing the Multiple Protostellar System VLA 1623-2417 with JWST, ALMA, and VLA: Outflow Origins, Dust Growth, and an Unsettled Disk
(Institute of Physics (IOP), 2025-03) Forbrich, Jan; Girart, Josep M.; Hoare, Melvin G.; Hernández Garnica, Ricardo; Jiménez-Serra, Izaskun; Loinard, Laurent; Ordóñez-Toro, Jazmín; Podio, Linda; Radley, Isaac C.; Busquet Rico, Gemma; Ilee, John D.; Liu, Hauyu Baobab; Pineda, Jaime E.; Pontoppidan, Klaus M.; Macías, Enrique; Maureira, María José; Bianchi, Eleonora; Bourke, Tyler L.; Codella, Claudio
Utilizing the James Webb Space Telescope (JWST), the Atacama Large Millimeter/submillimeter Array (ALMA), and the Very Large Array (VLA), we present high angular resolution (0 06–0 42), multiwavelength (4 μm–3 cm) observations of the VLA 1623-2417 protostellar system to characterize the origin, morphology and, properties of the continuum emission. JWST observations at 4.4 μm reveal outflow cavities for VLA 1623 A and, for the first time, VLA 1623 B, as well as scattered light from the upper layers of the VLA 1623 W disk. We model the millimeter-centimeter spectral energy distributions to quantify the relative contributions of dust and ionized gas emission, calculate dust masses, and use spectral index maps to determine where optical depth hinders this analysis. In general, all objects appear to be optically thick down to ∼90 GHz, show evidence for significant amounts (tens to hundreds of M_⊕) of large (>1 mm) dust grains, and are dominated by ionized gas emission for frequencies ≲15 GHz. In addition, we find evidence of unsettled millimeter dust in the inclined disk of VLA 1623 B possibly attributed to instabilities within the circumstellar disk, adding to the growing catalog of unsettled Class 0/I disks. Our results represent some of the highest-resolution observations possible with current instrumentation, particularly in the case of the VLA. However, our interpretation is still limited at low frequencies (≲22 GHz) and thus motivates the need for next-generation interferometers operating at centimeter wavelengths.
ALMA-IMF: XIX. C18O (J = 2─1): Measurements of turbulence in 15 massive protoclusters
(EDP Sciences, 2025-10) Busquet Rico, Gemma; Braine, J.; Liu, H.-L.; Csengeri, T.; Gusdorf, A.; Fernández-López, Manuel; Cunningham, N.; Bronfman, L.; Bonfand, Mélisse; Koley, Atanu; Stutz, Amelia; Louvet, F.; Motte, Frédérique; Ginsburg, A.; Galván-Madrid, Roberto; Álvarez-Gutiérrez, Rodrigo H.; Sanhueza, Patricio; Baug, T.; Sandoval-Garrido, N.; Salinas, J.
ALMA-IMF is a Large Program of the Atacama Large Millimeter/submillimeter Array (ALMA) that aims to determine the origin of the core mass function (CMF) of 15 massive Galactic protoclusters (~1.0─25.0 × 10³ M_⊙ within ~2.5 × 2.5 pc²) located toward the Galactic plane. In addition, the objective of the program is to obtain a thorough understanding of their physical and kinematic properties. Here we study the turbulence in these protoclusters with the C¹⁸O (2─1) emission line using the sonic Mach number analysis (M_s) and the size-linewidth relation. The probability distribution functions (PDFs) for M_s show a similar pattern, exhibiting no clear trend associated with evolutionary stage, peaking in the range between 4 and 7, and then extending to ~25. Such values of M_s indicate that the turbulence in the density regime traced by the C¹⁸O line inside the protoclusters is supersonic in nature. In addition, we compared the non-thermal velocity dispersions (σ_nth,C¹⁸_O) obtained from the C¹⁸O (2─1) line with the non-thermal line widths (σ_{nth, DCN}) of the cores obtained from the DCN (3─2) line. We observed that, on average, the non-thermal linewidth in cores is half that of the gas surrounding them. This suggests that turbulence diminishes at smaller scales or dissipates at the periphery of the cores. Furthermore, we examined the size-linewidth relation for the structures we extracted from the position-position-velocity C¹⁸O (2─1) line emission cube with the dendrogram algorithm. The power-law index (p) obtained from the size-linewidth relation is between 0.41 and 0.64, steeper than the Kolmogorov law of turbulence, as expected for compressible media. In conclusion, this work is one of the first to carry out a statistical study of turbulence for embedded massive protoclusters.
ALMA-IMF: XVIII. The assembly of a star cluster: Dense N2H+ (1─0) kinematics in the massive G351.77 protocluster
(EDP Sciences, 2025-04) Koley, Atanu; Sanhueza, Patricio; Bernal-Mesina, G.; Braine, J.; Bronfman, L.; Busquet Rico, Gemma; Csengeri, T.; Di Francesco, James; Fernández-López, Manuel; Garcia, Pablo; Sandoval-Garrido, Nicolás A.; Stutz, Amelia; Álvarez-Gutiérrez, Rodrigo H.; Galván-Madrid, Roberto; Motte, Frédérique; Ginsburg, A.; Cunningham, N.; Reyes-Reyes, S.; Redaelli, E.; Bonfand, Mélisse; Gusdorf, A.; Salinas, J.; Liu, H.-L.
ALMA-IMF observed 15 massive protoclusters capturing multiple spectral lines and the continuum emission. Here, we focus on the massive protocluster G351.77 (~2500 M⊙, estimated from single-dish continuum observations) located at 2 kpc. We trace the dense gas emission and kinematics with N2H+ (1–0) at ~4 kau resolution. We estimate an N2H+ relative abundance of ~(1.66 ± 0.46) × 10−10. We decompose the N2H+ emission into up to two velocity components, highlighting the kinematic complexity in the dense gas. By examining the position-velocity (PV) and position-position-velocity (PPV) diagrams on small scales, we observe clear inflow signatures (V-shapes) associated with 1.3 mm cores. The most prominent V-shape has a mass inflow rate of ~13.45 × 10−4 M⊙ yr−1 and a short timescale of ~11.42 kyr. We also observe V-shapes without associated cores. This suggests both that cores or centers of accretion exist below the 1.3 mm detection limit, and that the V-shapes may be viable tracers of very early accretion and star formation on ~4 kau scales. The large-scale PV diagram shows that the protocluster is separated into two principal velocity structures separate by ~2 km s−1. Combined with smaller-scale DCN and H2CO emission in the center, we propose a scenario of larger-scale slow contraction with rotation in the center based on simple toy models. This scenario is consistent with previous lines of evidence, and leads to the new suggestion of outside-in evolution of the protocluster as it collapses. The gas depletion times implied by the V-shapes are short (~0.3 Myr), requiring either very fast cluster formation, and/or continuous mass feeding of the protocluster. The latter is possible via the Mother Filament that G351.77 is forming out of. The remarkable similarities in the properties of G351.77 and the recently published work in G353.41 indicate that many of the physical conditions inferred via the ALMA-IMF N2H+ observations may be generic to protoclusters.
Erosion of a dense molecular core by a strong outflow from a massive protostar
(EDP Sciences, 2025-03) López-Vázquez, Jesús Alejandro; Fernández-López, Manuel; Girart, Josep Miquel; Curiel, Salvador; Estalella, Robert; Busquet Rico, Gemma; Zapata, Luis; Lee, Chin-Fei; Galván-Madrid, Roberto
Context. Molecular outflows from massive protostars can impact the interstellar medium in different ways, adding turbulence on different spatial scales, dragging material at supersonic velocities, producing shocks and heating, and physically impinging onto dense structures that may be harboring other protostars. Aims. We aim to quantify the impact of the outflow associated with the high-mass protostar GGD 27-MM2(E) on its parent envelope and how this outflow affects its environment. Methods. We present Atacama Large Millimeter/submillimeter Array Band 3 observations of N₂H⁺ (1–0) and CH₃CN (5–4), as well as Band 7 observations of the H₂CO molecular line emissions from the protostellar system GGD 27-MM2(E). Through position–velocity diagrams along and across the outflow axis, we studied the kinematics and structure of the outflow. We also fit extracted spectra of the CH₃CN emission to obtain the physical conditions of the gas. We use the results to discuss the impact of the outflow on its surroundings. Results. We find that N₂H⁺ emission traces a dense molecular cloud surrounding GGD 27-MM2(E). We estimate that the mass of this cloud is ~13.3–26.5 M_⊙. The molecular cloud contains an internal cavity aligned with the H₂CO-traced molecular outflow. The outflow, also traced by CH₃CN, shows evidence of a collision with a molecular core (MC), as indicated by the distinctive increases in the distinct physical properties of the gas such as the excitation temperature, column density, line width, and velocity. This collision results in an X-shaped structure in the northern part of the outflow around the position of the MC, which produces spray-shocked material downstream in the north of MC, as observed in position–velocity diagrams both along and across the outflow axis. The outflow has a mass of 1.7–2.1 M_⊙, a momentum of 7.8–10.1 M_⊙ km s^‑1, a kinetic energy of 5.0–6.6×10⁴⁴ erg, and a mass-loss rate of 4.9–6.0×10^‑4 M_⊙ yr^‑1. Conclusions. The molecular outflow from GGD 27-MM2(E) significantly perturbs and erodes its parent cloud, compressing the gas of sources such as the MC and ALMA 12. The feedback from this powerful protostellar outflow helps maintain the turbulence in the surrounding area.
The SOFIA Massive (SOMA) star formation Q-band follow-up: II. Hydrogen recombination lines towards high-mass protostars
(EDP Sciences, 2025-10) Gaches, Brandt A. L.; Saberi, Maryam; Das, Ankan; Gorai, Prasanta; Taniguchi, Kotomi; Tan, Jonathan C.; Gómez-Garrido, Miguel; Rosero, Viviana; Jiménez-Serra, Izaskun; Zhang, Yichen; Cosentino, Giuliana; Law, Chi-Yan; Fedriani, Rubén; Busquet Rico, Gemma
Context. Hydrogen recombination lines (HRLs) are valuable diagnostics of the physical conditions in ionized regions surrounding high-mass stars. Understanding these lines, including broadening mechanisms and intensity trends, can provide insights into HII region densities, temperatures, and kinematics. Aims. This study aims to investigate the physical properties of ionized gas around massive protostars by analysing the HRLs (Hα and Hβ) in the Q band. Methods. We carried out observations using the Yebes 40m radio telescope in the Q band (30.5─50 GHz) towards six high-mass protostars selected from the SOMA Survey (G45.12+0.13, G45.47+0.05, G28.20−0.05, G35.20−0.74, G19.08−0.29, and G31.28+0.06). The observed line profiles were analysed to assess broadening mechanisms, and electron densities and temperatures were derived. The results were compared with available Q-band data from the TianMa 65-m Radio Telescope (TMRT) that have been reported in the literature, and ALMA Band 1 (35─50 GHz) Science Verification observations towards Orion KL, analysed in this study. Results. A total of eight Hα (n = 51 to 58) and ten Hβ (n = 64 to 73) lines were detected towards G45.12+0.13, G45.47+0.05, and G28.20−0.05; there were no detections in other sources. We derived electron densities of ~1−5 × 10⁶ cm⁻³ and temperatures of 8000─10 000 K for the sources. However, for Orion KL, we obtained an electron density one order of magnitude lower, while its temperature was found to be more similar. Interestingly, G45.12 and G28.20 show an increasing intensity trend with frequency for both Hα and Hβ transitions, contrary to the decreasing trend observed in Orion KL. Conclusions. The line widths of the detected HRLs indicate contributions from both thermal and dynamical broadening, suggesting the presence of high-temperature ionized gas that is likely kinematically broadened (e.g. due to turbulence, outflows, rapid rotation, or stellar winds). Pressure broadening caused by electron density may also have a minor effect. We discuss different scenarios to explain the measured line widths of the HRLs. The contrasting intensity trends between the sources may reflect variations in local physical conditions or radiative transfer effects, highlighting the need for further investigation through higher-resolution observations and detailed modelling.
Evidence for Jet/Outflow Shocks Heating the Environment around the Class I Protostellar Source Elias 29: FAUST XXI
(Institute of Physics (IOP), 2025-02) Oya, Yoko; Saiga, Eri; Miotello, Anna; Koutoulaki, Maria; Johnstone, Doug; Ceccarelli, Cecilia; Chandler, Claire J.; Codella, Claudio; Sakai, Nami; Bianchi, Eleonora; Bouvier, Mathilde; Charnley, Steven; Busquet Rico, Gemma; et al.
We have observed the late Class I protostellar source Elias 29 at a spatial resolution of 70 au with the Atacama Large Millimeter/submillimeter Array as part of the FAUST Large Program. We focus on the line emission of SO, while that of ³⁴SO, C¹⁸O, CS, SiO, H¹³CO⁺, and DCO⁺ are used supplementarily. The spatial distribution of the SO rotational temperature (T_rot(SO)) is evaluated by using the intensity ratio of its two rotational excitation lines. Besides in the vicinity of the protostar, two hot spots are found at a distance of 500 au from the protostar; T_rot(SO) locally rises to 53 K at the interaction point of the outflow and the southern ridge, and 72 K within the southeastern outflow probably due to a jet-driven bow shock. However, the SiO emission is not detected at these hot spots. It is likely that active gas accretion through the disk-like structure and onto the protostar still continues even at this evolved protostellar stage, at least sporadically, considering the outflow/jet activities and the possible infall motion previously reported. Interestingly, T_rot(SO) is as high as 20–30 K even within the quiescent part of the southern ridge apart from the protostar by 500–1000 au without clear kinematic indication of current outflow/jet interactions. Such a warm condition is also supported by the low deuterium fractionation ratio of HCO⁺ estimated by using the H¹³CO⁺ and DCO⁺ lines. The B-type star HD147889 ∼0.5 pc away from Elias 29, previously suggested as a heating source for this region, is likely responsible for the warm condition of Elias 29.
Enhancing the detection of low-energy M dwarf flares: wavelet-based denoising of CHEOPS data
(EDP Sciences, 2024-12-24) Poyatos, Julien; Fors Aldrich, Octavi; Gómez Cama, José María; Ribas Canudas, Ignasi
Stellar flares are powerful bursts of electromagnetic radiation triggered by magnetic reconnection in the chromosphere of stars, occurring frequently and intensely on active M dwarfs. While missions like TESS and Kepler have studied regular and super-flares, their detection of flares with energies below 10^30 erg remains incomplete. Extending flare studies to include these low-energy events could enhance flare formation models and provide insight into their impacts on exoplanetary atmospheres. This study investigates CHEOPS's capacity to detect low-energy flares in M dwarf light curves. Using CHEOPS's high photometric precision and observing cadence, along with a tailored wavelet-based denoising algorithm, we aim to improve detection completeness and refine flare statistics for low-energy events. We conducted a flare injection and recovery process to optimise denoising parameters, applied it to CHEOPS light curves to maximise detection rates, and used a flare breakdown algorithm to analyse complex structures. Our analysis recovered 349 flares with energies ranging from 2.2×10^26 to 8.1×10^30 erg across 63 M dwarfs, with ∼40% exhibiting complex, multi-peaked structures. The denoising algorithm improved flare recovery by ∼34%, though it marginally extended the lower boundary of detectable energies. For the full sample, the power-law index α was 1.92±0.07, but a log-normal distribution fit better, suggesting multiple flare formation scenarios. While CHEOPS's observing mode is not ideal for large-scale surveys, it captures weaker flares than TESS or Kepler, expanding the observed energy range. Wavelet-based denoising enhances low-energy event recovery, enabling exploration of the micro-flaring regime. Expanding low-energy flare observations could refine flare generation models and improve the understanding of their role in star-planet interactions.
The production of orbitally modulated UHE photons in LS 5039
(EDP Sciences, 2025-08) Bosch i Ramon, Valentí; Khangulyan, Dmitry
Conntext. Gamma-ray binaries present emission that is variable and can reach ultra-high energies. The processes behind the acceleration of the particles that produce this very energetic radiation are yet to be understood. Aims. We probe the properties of the particle accelerator and the ultra-high-energy photon emitter in the gamma-ray binary LS 5039. Methods. From the properties of the binary system and the ultra-high-energy radiation detected by HAWC, we used analytical tools to investigate how these properties constrain the emission and acceleration regions, namely the role of synchrotron losses, particle confinement, and the accelerated particle spectrum, and propose an acceleration scenario that can relax the derived constraints. Results. The modest target densities for hadronic processes and the overall gamma-ray orbital variability favor inverse Compton scattering of ultraviolet photons from the massive companion star by highly relativistic electrons. The acceleration of the highest energy electrons implies a constraint on synchrotron cooling in the acceleration region, which can set an upper limit on its magnetic field. Moreover, the detected variability requires very strong particle confinement in both the acceleration and emission regions, which sets a lower limit on their magnetic fields that is barely consistent with the synchrotron cooling constraint from acceleration. Synchrotron losses may be higher in the emitting region if it is separated from the accelerator, but this requires a very hard particle injection spectrum. An accelerator based on an ultrarelativistic magnetized outflow can alleviate these requirements. Conclusions. A scenario for LS 5039 of the kind proposed by Derishev and collaborators, in which an ultrarelativistic magnetized outflow accelerates leptons injected within the outflow by γγ absorption, provides a viable mechanism to accelerate very energetic electrons. This mechanism relaxes the acceleration and confinement requirements by reducing the impact of synchrotron cooling, and can generate the required particle spectrum.
C60 fullerene as an on-demand single photon source at room temperature
(American Chemical Society, 2025-10-03) Lahoz Sanz, Raul; Lozano Martín, Lidia; Brú Cortés, Adrià; Hernández Márquez, Sergi; Duocastella, Martí; Gómez Cama, José María; Juliá-Díaz, Bruno
Single photon sources are fundamental for applications in quantum computing, secure communication, and sensing, as they enable the generation of individual photons and ensure strict control over photon number statistics. However, current single photon sources can be limited by a lack of robustness, difficulty of integration into existing optical or electronic devices, and high cost. In this study, we present the use of off-the-shelf C60 fullerene molecules embedded in polystyrene as room-temperature reliable single-photon emitters. As our results demonstrate, these molecules exhibit on-demand single-photon emission, with short fluorescence lifetimes and, consequently, high emission rates. The wide availability and ease of preparation and manipulation of fullerenes as single photon sources can pave the way for the development of practical, economic and scalable quantum photonic technologies.
Using clustering for disperse objects fields segmentation in MIRADAS instrument
(Society of Photo-Optical Instrumentation Engineers (SPIE), 2018-07-06) Sabater, Josep; Torres Álvarez, Santiago; Garzón López, Francisco; Gómez Cama, José María
Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is a near-infrared multi-object spectrograph for Gran Telescopio Canarias (GTC). It has 12 deployable Integral Field Units (IFU) based on probe arms with pick-off mirrors, each of which can observe a different user-defined sky object. MIRADAS can work with target sets where their components are spread over such a wide area so that all of them do not fit in the field-of-view of the instrument. Therefore, data sets of that kind require, prior to capturing them, some arrangement that groups its elements in different subsets where the distance between the two most remote elements is inferior to the field-of-view diameter. This field segmentation is achieved using a hierarchical clustering technique. Our method relies on determining mutual nearest-neighbors, which will be merged if they show a given degree of similarity known beforehand. Moreover, we also compute a geometric center for these clusters, information to be delivered to the telescope’s pointing process. This step is formulated as the minimum bounding disk problem, which founds the center of the smallest radius circle enclosing all points of a cluster. Finally, we consider several real science cases and analyze the performance of the proposed solution.
Gaia's Cepheids and RR Lyrae stars and luminosity calibrations based on Tycho-Gaia Astrometric Solution
(EDP Sciences, 2017-09-08) Clementini, Gisella; Eyer, Laurent; Muraveva, Tatiana; Garofalo, A.; Ripepi, Vincenzo; Marconi, Marcella; Sarro, Luis M.; Palmer, Max; Luri Carrascoso, Xavier; Molinaro, Roberto; Rimoldini, Lorenzo; Szabados, Laszlo; Anderson, Richard I.; Musella, Ilaria
Gaia Data Release 1 contains parallaxes for more than 700 Galactic Cepheids and RR Lyrae stars, computed as part of the Tycho-Gaia Astrometric Solution (TGAS). We have used TGAS parallaxes, along with literature (V, I, J, Ks, W1) photometry and spectroscopy, to calibrate the zero point of the period-luminosity and period-Wesenheit relations of classical and type II Cepheids, and the near-infrared period-luminosity, period-luminosity-metallicity and optical luminosity-metallicity relations of RR Lyrae stars. In this contribution we briefly summarise results obtained by fitting these basic relations adopting different techniques that operate either in parallax or distance (absolute magnitude) space

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