Journal article
Evolution of compact groups from intermediate to final stages A case study of the H I content of HCG16
Astronomy and astrophysics (Berlin), Vol.632, 78
12/03/2019
DOI: 10.1051/0004-6361/201936349
Abstract
Context. Hickson Compact Group (HCG) 16 is a prototypical compact group of galaxies in an intermediate stage of the previously proposed evolutionary sequence, where its galaxies are losing gas to the intra-group medium (IGrM). The group hosts galaxies that are H I-normal, H I-poor, and centrally active with both AGNs and starbursts, in addition to a likely new member and a H I tidal feature of similar to 160 kpc in length. Despite being a well-studied group at all wavelengths, no previous study of HCG16 has focused on its extraordinary H I component.
Aims. The characteristics of HCG16 make it an ideal case study for exploring which processes are likely to dominate the late stages of evolution in compact groups, and ultimately determine their end states. In order to build a coherent picture of the evolution of this group we make use of the multi-wavelength data available, but focus particularly on H I as a tracer of interactions and evolutionary phase.
Methods. We reprocess archival VLA L-band observations of HCG16 using the multi-scale CLEAN algorithm to accurately recover diffuse features. Tidal features and galaxies are separated in three dimensions using the SlicerAstro package. The H I deficiency of the separated galaxies is assessed against the benchmark of recent scaling relations of isolated galaxies. This work has been performed with particular attention to reproducibility and is accompanied by a complete workflow to reproduce all the final data products, figures, and results.
Results. Despite the clear disruption of the H I component of HCG16 we find that it is not globally H I deficient, even though HCG16a and b have lost the majority of their H I and almost 50% of the group's H I is in the IGrM. The H I content of HCG16d shows highly disturbed kinematics, with only a marginal velocity gradient that is almost perpendicular to its optical major axis. The tail of similar to 160 kpc in length extending towards the southeast appears to be part of an even larger structure which spatially and kinematically connects NGC848 to the northwest corner of the group.
Conclusions. This study indicates that in the recent past (similar to 1 Gyr) galaxies HCG16a and b likely underwent major interactions that unbound gas without triggering significant star formation. This gas was then swept away by a close, high-speed encounter with NGC848. The starburst events HCG16c and d, likely initiated by their mutual interaction, triggered galactic winds which, in the case of HCG16d, appear to have disrupted its H I reservoir. The tidal features still connected to all these galaxies indicate that more H I will soon be lost to the IGrM, while that which remains in the discs will likely be consumed by star-formation episodes triggered by their ongoing interaction. This is expected to result in a collection of gas-poor galaxies embedded in a diffuse H I structure, which will gradually (over several Gyr) be evaporated by the UV background, resembling the final stage of the evolutionary model of compact groups.
Details
- Title: Subtitle
- Evolution of compact groups from intermediate to final stages A case study of the H I content of HCG16
- Creators
- M. G. Jones - Instituto de Astrofísica de AndalucíaL. Verdes-Montenegro - CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, SpainA. Damas-Segovia - Instituto de Astrofísica de AndalucíaS. Borthakur - Arizona State UniversityM. Yun - University of Massachusetts AmherstA. del Olmo - Instituto de Astrofísica de AndalucíaJ. Perea - Instituto de Astrofísica de AndalucíaJ. Roman - Instituto de Astrofísica de AndalucíaS. Luna - CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, SpainD. Lopez Gutierrez - Macalester Coll, Dept Phys & Astron, 1600 Grand Ave, St Paul, MN 55105 USAB. Williams - European Southern ObservatoryF. P. A. Vogt - University of DelawareJ. Garrido - Instituto de Astrofísica de AndalucíaS. Sanchez - CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, SpainJ. Cannon - Macalester CollegeP. Ramirez-Moreta - CSIC, Inst Astrofis Andalucia, Glorieta Astron, E-18008 Granada, Spain
- Resource Type
- Journal article
- Publication Details
- Astronomy and astrophysics (Berlin), Vol.632, 78
- Publisher
- Edp Sciences S A
- DOI
- 10.1051/0004-6361/201936349
- ISSN
- 0004-6361
- eISSN
- 1432-0746
- Number of pages
- 36
- Grant note
- Juan de la Cierva formacion fellowship AYA2015-65973-C3-1-R; RTI2018-096228-B-C31 / MINECO/FEDER, UE; Spanish Government National Aeronautics and Space Administration; National Aeronautics & Space Administration (NASA) SEV-2017-0709 / Spanish Science Ministry "Centro de Excelencia Severo Ochoa" program; Spanish Government
- Language
- English
- Date published
- 12/03/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627245502771
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