J/A+A/695/A206 BEINGMgII. I. galaxies with USMgII absorbers (Joshi+, 2025)
Baryonic Ecosystem IN Galaxies (BEINGMgII).
I. Host galaxies of ultra-strong Mg II absorbers in Subaru Hyper Suprime-Cam
Survey.
Joshi R., Das S., Fumagalli M., Fossati M., Peroux C., Chaudhary R.,
Yesuf M.H., Ho C.L.
<Astron. Astrophys. 695, A206 (2025)>
=2025A&A...695A.206J 2025A&A...695A.206J (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Galaxies, optical ; Galaxies, spectra
Keywords: galaxies: evolution - galaxies: halos - galaxies: high-redshift -
galaxies: ISM - quasars: absorption lines - galaxies: star formation
Abstract:
We study the galaxies hosting ultra-strong MgII (USMgII) absorbers at
small impact parameters of ∼2" (5-20kpc), spanning a redshift range of
0.4≤z≤1.7, using deep, high-resolution images from Hyper Suprime-Cam
Subaru Strategic Survey and spectra from SDSS survey.
To explore the physical origin of USMgII absorbers and characterize
the associated galaxies.
We performed a galaxy spectral energy distribution fitting using
optical and near-IR multi-band data to identify the potential absorber
host galaxies. Further, we search for [OII] nebular emission line from
absorber galaxy in the SDSS fiber spectra.
From a total of 418 USMgII absorbers with W2796≥3Å along 412
quasar sightlines, we detect 50 galaxies based on [OII]
λλ3727,3729 nebular emission detected at ≥2σ
level. Utilizing the [OII] emission from the stacked spectrum and
employing the best-fit galaxy SED template, we further identify 86
galaxies, leading to a total of 136 bona fide USMgII galaxies. With a
prerequisite of having a minimum of four HSC passbands available, we
find a detection rate of ∼38% at an average impact parameter of
11.4kpc. We find that galaxies hosting USMgII systems are typically
star-forming main sequence galaxies, with 21% exhibiting a starburst
nature. The non-zero [OII] emission along the 'clear' sightlines, with
no stellar counterpart, hints that the USMgII absorbers may likely
emanate from the unseen faint galaxies near the quasar. The USMgII
absorbers preferentially align along the major and minor axes of the
galaxy, which suggests that they originate in the disk or large-scale
wind. We show that the distribution of W2796 as a function of impact
parameter indicates a discernible radial dependence for the 'disk' and
'wind' subsets, with the observed large scatter in W2796 potentially
attributed to large-scale outflows. The quasar sightline hosting
USMgII systems show a factor three higher galaxy surface density at
impact parameters of ≲50kpc, highlights the multiple pathways giving
rise to USMgII absorption.
Description:
Utilizing the deep, high-resolution optical imaging data provided
by the Subaru HSC-SSP survey, we investigated the characteristics of
galaxies associated with USMgII absorbers. Augmented by deep IR
imaging data from the VISTA survey and spectral data from the SDSS
survey, we have identified 136 USMgII galaxies in proximity to quasars
across a broad redshift range of 0.4≤z≤1.7.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
catalog.dat 118 136 Physical properties of galaxies associated with
USMgII absorbers
--------------------------------------------------------------------------------
See also:
J/A+A/695/A207 : BEINGMgII. II Galaxies with strong MgII absorbers (Das+, 2025)
Byte-by-byte Description of file: catalog.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- QSO SDSS J2000 quasar name (JHHMMSS.ss+DDMMSS.s)
21- 26 F6.4 --- zabs MgII absorber redshift
28- 31 F4.2 0.1nm Wr2796 MgII 2796Å rest equivalent width
33- 36 F4.2 0.1nm e_Wr2796 Error on the MgII 2796Å
rest equivalent width
38- 41 F4.2 0.1nm Wr2803 MgII 2803Å rest equivalent width
43- 46 F4.2 0.1nm e_Wr2803 Error on the MgII 2803Å
rest equivalent width
48- 56 F9.5 deg RAdeg Galaxy right ascension (J2000)
58- 66 F9.5 deg DEdeg Galaxy declination (J2000)
68- 71 F4.1 kpc rho Impact parameter
73- 76 F4.1 deg phi ?=- Azimuthal angle
78- 82 F5.2 [Msun] b_logMstar ?=- Stellar mass lower bound
84- 88 F5.2 [Msun] logMstar ?=- Stellar mass
90- 94 F5.2 [Msun] B_logMstar ?=- Stellar mass upper bound
96-101 F6.2 Msun/yr b_SFR ?=- Star formation rate lower bound
103-108 F6.2 Msun/yr SFR ?=- Star formation rate
110-115 F6.2 Msun/yr B_SFR ?=- Star formation rate upper bound
117-118 A2 --- Category [1A 1B 3A] Detection set
--------------------------------------------------------------------------------
Acknowledgements:
Ravi Joshi, ravi.joshi(at)iiap.res.in
References:
Das et al., Paper II 2025A&A...695A.207D 2025A&A...695A.207D
(End) Patricia Vannier [CDS] 10-Feb-2025