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Title: DIISC-III. Signatures of Stellar Disk Growth in Nearby Galaxies
Abstract We explore the growth of the stellar disks in 14 nearby spiral galaxies as part of the Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey. We study the radial distribution of specific star formation rates (sSFRs) and investigate the ratio of the difference in the outer and inner sSFRs (ΔsSFR= sSFRout– sSFRin) of the disk and the total sSFR, ΔsSFR/sSFR, to quantify disk growth. We find ΔsSFR/sSFR and the Higas fraction to show a mild correlation of Spearman’sρ= 0.30, indicating that star formation and disk growth are likely to proceed outward in galactic disks with high Higas fractions. The Higas fractions and ΔsSFR/sSFR of the galaxies also increase with the distance to the nearestL⋆neighbor, suggesting that galaxies are likely to sustain the cold gas in their interstellar medium and exhibit inside-out growth in isolated environments. However, the Hicontent in their circumgalactic medium (CGM), probed by the Lyαequivalent width (WLyα) excess, is observed to be suppressed in isolated environments, as is apparent from the strong anticorrelation between theWLyαexcess and the distance to the fifth nearestL⋆neighbor (Spearman’sρ= −0.62). As expected,WLyαis also found to be suppressed in cluster galaxies. We find no relation between theWLyαexcess of the detected CGM absorber and ΔsSFR/sSFR, implying that the enhancement and suppression of the circumgalactic Higas does not affect the direction in which star formation proceeds in a galactic disk or vice versa.  more » « less
Award ID(s):
2009409
PAR ID:
10549800
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
Astrophysical Journal
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
960
Issue:
1
ISSN:
0004-637X
Page Range / eLocation ID:
24
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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