J/A+A/672/A139 KiDS 1433 CO spectra (Castignani+, 2023)
Star-forming brightest cluster galaxies at z∼0.4 in KiDS.
Further studies of cold gas and stellar properties.
Castignani G., Radovich M., Combes F., Salome P., Moscardini L.,
Bardelli S., Giocoli C., Lesci G., Marulli F., Maturi M., Puddu E.,
Sereno M., Tramonte D.
<Astron. Astrophys. 672, A139 (2023)>
=2023A&A...672A.139C 2023A&A...672A.139C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Spectra, radio ; Carbon monoxide
Keywords: galaxies: clusters: general - galaxies: star formation -
galaxies: evolution - galaxies: active - molecular data
Abstract:
Brightest cluster galaxies (BCGs) at the centers of clusters are among
the most massive galaxies in the Universe. Their star formation
history and stellar mass assembly are highly debated. Recent studies
suggest the presence of an emerging population of intermediate-z
star-forming and gas-rich BCGs, whose molecular gas reservoirs that
feed star formation might be impacted by strong environmental
processing. We have selected three of the most strongly star-forming
z∼0.4 BCGs in the equatorial field of the Kilo-Degree Survey (KiDS)
and observed them with the IRAM 30m telescope in the first three CO
transitions. We found clear double-horn CO(1-->0) and CO(3-->2)
emission for the KiDS 1433 BCG, yielding a large molecular gas
reservoir with MH2=(5.9±1.2)1010M☉ and a high
gas-to-stellar mass ratio MH2/M*=(0.32+0.12-0.10). We thus
increase the still limited sample of distant BCGs with detections in
multiple CO transitions. The double-horn emission for the KiDS 1433
BCG implies a low gas concentration, while a modeling of the spectra
yields an extended molecular gas reservoir, with a characteristic
radius of (5-7) kpc, which is reminiscent of the mature extended-disk
phase that is observed in some local BCGs. For the remaining two BCGs,
we are able to set robust upper limits of MH2/M*<0.07 and <0.23,
which are among the lowest for distant BCGs.We then combined our
observations with available stellar, star formation, and dust
properties of the targeted BCGs, and compared them with a sample of
∼100 distant cluster galaxies, including additional intermediate-z
BCGs, with observations in CO from the literature. Altogether, our
analysis shows that the molecular gas properties of star-forming BCGs
are heterogeneous. On the one hand, gas-rich BCGs show extended gas
reservoirs that sustain the significant star formation activity, but
the efficiency is low, which is reminiscent of recent gas infall. On
the other hand, the existence of similarly star forming but gas-poor
BCGs suggests that gas depletion precedes star formation quenching.
Description:
Baseline-subtracted CO(1-->0) and CO(3-->2) spectra of KiDS 1433.
Objects:
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RA (2000) DE Designation(s)
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14 33 29.13 +02 07 23.36 KiDS 1433 (SDSS J143329.12+020723.3)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
co10.dat 22 232 Baseline-subtracted CO(1-->0) spectrum
co32.dat 22 93 Baseline-subtracted CO(3-->0) spectrum
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See also:
II/347 : KiDS-ESO-DR3 multi-band source catalog (de Jong+, 2017)
Byte-by-byte Description of file: co10.dat co32.dat
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Bytes Format Units Label Explanations
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2- 10 F9.2 km/s Vel Velocity
12- 22 E11.5 mJy Flux Flux
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Acknowledgements:
Gianluca Castignani, gianluca.castignani(at)unibo.it
(End) Patricia Vannier [CDS] 27-Mar-2023