J/A+A/704/A264 Starbursts galaxies in Hydra I cluster (de la Casa+, 2025)
Starburst galaxies in the Hydra I cluster.
de la Casa C.C., Hess K.M., Verdes-Montenegro L. Kotulla R., Chen H.,
Jarrett T.H., Cluver M.E., De Daniloff S.B., Gendron-Marsolais M.-L.,
Carignan C., Gallagher J.S. III, Kraan-Korteweg R.C., Ianjamasimanana R.
<Astron. Astrophys. 704, A264 (2025)>
=2025A&A...704A.264D 2025A&A...704A.264D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, nearby ; Photometry, ugriz ;
Photometry, H-alpha ; Magnitudes, absolute
Keywords: galaxies: clusters : general - galaxies: evolution -
galaxies: interactions - galaxies: starburst -
galaxies: star formation
Abstract:
Studying the impact of environment on star formation and quenching
pathways requires statistically relevant samples of galaxies in a wide
mass range. We present a new catalog of 196 galaxies of the nearby
Hydra I cluster out to ∼1.75r200, consisting of broad u,g,r,i,z along
with narrowband Hα measurements. These deep optical images were
obtained with the DECam camera (CTIO) and reach down to a surface
brightness limit of µ(3σ; 10"x10")=26.9mag/arcsec2 in the g
band. We also report the HI properties for 89 cluster members detected
with MeerKAT. A color magnitude diagram (CMD) shows a bimodal
distribution typical of a cluster population, more evolved than those
found in isolation. We combine optical Hα and WISE infrared data
to compare the star formation history at two distinct timescales.
Differences in the star forming activity depicted by both populations
manifest as starburst in 24 found members. Of these, 18 starburst
galaxies have neutral gas measurements, and show disturbed HI disks
that suggest an environmentally triggered boost in star formation
within the last 107yrs. Processes such as ram pressure stripping or
tidal interactions may underlie their enhanced star-forming activity
and asymmetric disks. Since Hydra's dynamical history is unclear, we
examine the spatial and velocity distribution of the sample. We reveal
a possible link between the large scale structure feeding the Hydra I
cluster and the heightened star-forming activity of the starburst
galaxies. This feeding pattern matches the few substructure that has
been identified in Hydra in previous works, and may explain its
origin. Our results portray a picture of a cluster with an evolved
nature, plus a population of new infalling galaxies that manifest the
impact of their first contact with the cluster environment through
star formation, color, morphology and gas content transformations.
Description:
We present a new catalog of 196 galaxies of the nearby Hydra I cluster
out to ∼1.75r200, consisting of DECam broad u,g,r,i,z and narrowband
Hα, WISE mid-infrared, and MeerKAT HI.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables12.dat 205 196 Catalog of 196 galaxies of the nearby Hydra I
cluster out to ∼1.75r200
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Byte-by-byte Description of file: tables12.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID HydraSBGs catalog ID
5- 32 A28 --- Name Name of HydraSBGs galaxies from NED
34- 35 I2 h RAh Right ascension (J2000)
37- 38 I2 min RAm Right ascension (J2000)
40- 44 F5.2 s RAs Right ascension (J2000)
46 A1 --- DE- Declination sign (J2000)
47- 48 I2 deg DEd Declination (J2000)
50- 51 I2 arcmin DEm Declination (J2000)
53- 56 F4.1 arcsec DEs Declination (J2000)
58- 63 F6.4 --- z Redshift
65- 70 F6.3 mag uMAG Absolute value of absolute magnitude in
DECam's u band
72- 76 F5.3 mag e_uMAG Absolute value of the uncertainty in the
absolute magnitude in DECam's u band
78- 83 F6.3 mag gMAG Absolute value of absolute magnitude in
DECam's g band
85- 89 F5.3 mag e_gMAG Absolute value of the uncertainty in the
absolute magnitude in DECam's g band
91- 96 F6.3 mag rMAG Absolute value of absolute magnitude in
DECam's r band
98-102 F5.3 mag e_rMAG Absolute value of the uncertainty in the
absolute magnitude in DECam's r band
104-110 F7.3 mag iMAG ?=999 Absolute value of absolute magnitude
in DECam's i band
112-118 F7.3 mag e_iMAG ?=999 Absolute value of the uncertainty in
the absolute magnitude in DECam's i band
120-126 F7.3 mag zMAG ?=999 Absolute value of absolute magnitude
in DECam's z band
128-134 F7.3 mag e_zMAG ?=999 Absolute value of the uncertainty in
the absolute magnitude in DECam's z band
136-142 F7.4 [Msun/yr] SFRHa Star Formation Rate from DECam's
Halpha narrowband
144-149 F6.4 [Msun/yr] e_SFRHa Uncertainty in the Star Formation Rate from
DECam's Halpha narrowband
151 I1 --- lMAG [0/1] Upper limit (=1) flag for absolute
magnitudes
153 I1 --- l_SFRHa [0/1] Lower limit (=1) flag for SFRHa
155 I1 --- flagStar [0/1] Bright source (=1) in the field that
increases the uncertainty of the photometry
157-162 F6.4 Msun/yr SFRmIR Star Formation Rate from WISE survey
164-173 F10.4 Msun/yr e_SFRmIR ?=999 Uncertainty in the Star Formation Rate
from WISE survey
175-179 F5.2 [Msun] logSmass log10 of the stellar mass content from WISE
survey
181-184 F4.2 [Msun] e_logSmass Uncertainty of log10 of the stellar mass
content from WISE survey
186-191 F6.3 [Msun] logHImass ?=- log10 of the neutral gas content from
MeerKAT (if available)
193-205 F13.3 [Msun] e_logHImass ?=- Uncertainty of log10 of the neutral gas
content from MeerKAT (if available)
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Acknowledgements:
Clara C. de la Casa, clarac(at)iaa.es
(End) Patricia Vannier [CDS] 08-Oct-2025