Unveiling Sizes of Compact AGN Hosts with ALMA
Journal
Date Issued
2020
Author(s)
Chang, YY
•
Le Floc'h, E
•
Juneau, S
•
da Cunha, E
•
Salvato, M
•
Dekel, A
•
Civano, F
•
•
Suh, H
•
Wang, WH
Abstract
We present rest-frame far-infrared (FIR) and optical size measurements of active galactic nucleus (AGN) hosts and star-forming galaxies (SFGs) in the COSMOS field, enabled by high-resolution Atacama Large Millimeter/submillimeter Array (ALMA)/1 mm (0.1-0.4) and Hubble Space Telescope (HST)/F814W imaging (0.1). Our sample includes 27 galaxies at z < 2.5, classified as infrared-selected AGN (three sources), X-ray selected AGN (four sources), and non-AGN SFGs (20 sources), for which high-resolution Band 6/7 ALMA images are available at 1 mm from our own observing program as well as archival observations. The sizes and star formation rate surface densities measured from both ALMA/1 mm and HST/F814W images show that obscured AGN host galaxies are more compact than non-AGN SFGs at similar redshift and stellar mass. This result suggests that the obscured accretion phase may be related to galaxies experiencing a compaction of their gaseous component, which could be associated with enhanced central star formation before a subsequent quenching driving the formation of compact passive galaxies. Moreover, most of the detected and stacked rest-frame FIR sizes of AGNs in our sample are similar or more compact than their rest-frame optical sizes, which is consistent with recent results of ALMA-detected sources. This might be explained by the fact that the dusty starbursts take place in the compact regions, and suggests that the star formation mechanisms in the compact regions of AGN hosts are similar to those observed in SFGs observed with ALMA.
Volume
888
Issue
1
Start page
44
Issn Identifier
0004-637X
Ads BibCode
2020ApJ...888...44C
Rights
open.access
File(s)![Thumbnail Image]()
![Thumbnail Image]()
Loading...
Name
1911.07858.pdf
Description
preprint
Size
1.2 MB
Format
Adobe PDF
Checksum (MD5)
7ba2d1be7ab28230da2be3fd674971a1
Loading...
Name
Chang_2020_ApJ_888_44.pdf
Description
[Administrators only]
Size
1.14 MB
Format
Adobe PDF
Checksum (MD5)
77c10d0b070e01028b1178d4f1321587