J/ApJ/940/52 VLA 15 & 33GHz obs. of GOALS-ES galaxies (Song+, 2022)
Characterizing compact 15-33GHz radio continuum sources in local U/LIRGs.
Song Y., Linden S.T., Evans A.S., Barcos-Munoz L., Murphy E.J.,
Momjian E., Diaz-Santos T., Larson K.L., Privon G.C., Huang X., Armus L.,
Mazzarella J.M., U. V, Inami H., Charmandaris V., Ricci C., Emig K.L.,
McKinney J., Yoon I., Kunneriath D., Lai T.S.-Y., Rodas-Quito E.E.,
Saravia A., Gao T., Meynardie W., Sanders D.B.
<Astrophys. J., 940, 52 (2022)>
=2022ApJ...940...52S 2022ApJ...940...52S
ADC_Keywords: Galaxies, IR; Galaxies, nearby; Radio continuum;
Active gal. nuclei; Star Forming Region; Millimetric/submm sources
Keywords: Luminous infrared galaxies ; Radio continuum emission ;
Galaxy nuclei ; Very Large Array ; Star forming regions
Abstract:
We present the analysis of ∼100pc scale compact radio continuum
sources detected in 63 local (ultra)luminous infrared galaxies
(U/LIRGs; LIR≥1011L☉), using FWHM≲0.1"-0.2" resolution
15 and 33GHz observations with the Karl G. Jansky Very Large Array. We
identify a total of 133 compact radio sources with effective radii of
8-170pc, which are classified into four main categories-"AGN" (active
galactic nuclei), "AGN/SBnuc" (AGN-starburst composite nucleus),
"SBnuc" (starburst nucleus), and "SF" (star-forming clumps)-based on
ancillary data sets and the literature. We find that "AGN" and
"AGN/SBnuc" more frequently occur in late-stage mergers and have up
to 3dex higher 33GHz luminosities and surface densities compared with
"SBnuc" and "SF," which may be attributed to extreme nuclear starburst
and/or AGN activity in the former. Star formation rates (SFRs) and
surface densities (ΣSFR) are measured for "SF" and "SBnuc" using
both the total 33GHz continuum emission (SFR∼0.14-13M☉/yr,
ΣSFR∼13-1600M☉/yr/kpc2) and the thermal free-free
emission from HII regions (median SFRth∼0.4M☉/yr,
ΣSFRth∼44M☉/yr/kpc2). These values are 1-2dex higher
than those measured for similar-sized clumps in nearby normal
(non-U/LIRGs). The latter also have a much flatter median 15-33GHz
spectral index (~-0.08) compared with "SBnuc" and "SF" (~-0.46), which
may reflect higher nonthermal contribution from supernovae and/or
interstellar medium densities in local U/LIRGs that directly result
from and/or lead to their extreme star-forming activities on 100pc
scales.
Description:
The Great Observatories All-sky LIRG Survey (GOALS) "equatorial" radio
survey (GOALS-ES; see Linden+ 2019ApJ...881...70L 2019ApJ...881...70L) is a
multifrequency, multiresolution snapshot VLA survey designed to map
the brightest radio continuum emission in all 68 U/LIRGs from GOALS
(Armus+ 2009PASP..121..559A 2009PASP..121..559A) that have a decl. of |δ|<20°.
The VLA observations for the GOALS-ES utilizes three receiver bands:
the S band (2-4GHz), Ku band (12-18GHz), and Ka band (26.5-40GHz).
In this work, we focus on analyzing observations taken at the Ku band
(15GHz) and the Ka band (33GHz) in the A- and/or B-configurations
where the nuclear star-forming structures are resolved at
subkiloparsec scales at the distances of these U/LIRGs (i.e.,
DL∼100Mpc, 1"∼500pc).
A-configuration observations at the Ku band and Ka band were initially
carried out in two separate A-configuration cycles, from
2014-Mar-6--May-10 (14A-471, PI: A. Evans), and 2016-Oct-7--12
(16A-204, PI: S. Linden). Additional B-configuration observations at
the Ka band were carried out in 2020 (20A-401, PI: Y. Song).
Additionally, Ku-band observations for six systems from 14A-471 were
re-observed on Dec-10 (20B-313, PI: Y. Song).
To expand our study, in Section 5 we include comparisons between
properties of compact radio continuum sources detected in the GOALS-ES
systems and of those detected in other local U/LIRGs and nearby normal
galaxies. To do this, we utilize VLA continuum observations of 22 of
the most luminous local U/LIRGs presented in
Barcos-Munoz+ 2017ApJ...843..117B 2017ApJ...843..117B and of 56 nearby normal galaxies
from the Star Formation in Radio Survey (SFRS;
Murphy+ 2018, J/ApJS/234/24 and Linden+ 2020, J/ApJS/248/25).
See Section 2.3 and Appendix B.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 82 68 Basic properties of the Great Observatories
All-sky LIRG Survey - "equatorial" radio survey
(GOALS-ES) sample
table2.dat 112 133 Measured and derived quantities for regions
identified at native resolutions
table3.dat 133 115 *Measured and derived quantities for regions
identified at matched resolutions
tableb1.dat 89 23 Measured and derived quantities for BM17
(Barcos-Munoz+ 2017ApJ...843..117B 2017ApJ...843..117B) regions
in 14 galaxies
tableb2.dat 129 135 Measured and derived quantities for SFRS
(Murphy+ 2018, J/ApJS/234/24 and
Linden+ 2020, J/ApJS/248/25)
star-forming regions in 28 galaxies
--------------------------------------------------------------------------------
Note on table3.dat: For regions identified at 15 GHz, upper-limits are
provided for alpha, fth, logSFRth, and logSigmath. For unresolved
regions, the reported values are lower-limits, indicated with ">". For
the logSFR through logSigmath columns, we only report values for Types
"SF" and "SBnuc".
--------------------------------------------------------------------------------
See also:
VII/157 : The Extended 12um galaxy sample (Rush+ 1993)
VII/233 : 2MASS All-Sky Extended Source Catalog (XSC) (IPAC/UMass, 2003-2006)
J/AJ/102/1663 : Radio properties of extragal. IRAS sources (Condon+, 1991)
J/ApJ/378/65 : 8.4GHz observations of compact starbursts (Condon+ 1991)
J/AJ/109/2318 : Extragalactic IRAS sources (Condon+ 1995)
J/A+AS/132/181 : Very luminous IRAS galaxies spectra. II. (Wu+ 1998)
J/AJ/126/1607 : IRAS Revised Bright Galaxy Sample (Sanders+, 2003)
J/ApJ/622/772 : Redshift survey of submillimeter galaxies (Chapman+, 2005)
J/ApJ/723/993 : Spatial extent of (U)LIRGs in the MIR. I. (Diaz-Santos+, 2010)
J/ApJ/715/572 : GOALS UV and FIR properties (Howell+, 2010)
J/ApJ/709/884 : Role of starburst-AGN composites in LIRG mergers (Yuan+, 2010)
J/A+A/533/A119 : GOODS-Herschel North and South catalogs (Elbaz+, 2011)
J/A+A/528/A35 : Infrared luminosity in GOODS fields (Magnelli+, 2011)
J/ApJ/761/97 : Star Formation in Radio Survey (SFRS): 33GHz (Murphy+, 2012)
J/ApJ/768/102 : I-band GALFIT analysis of luminous IR galaxies (Kim+, 2013)
J/ApJ/765/L26 : Swift/BAT ultra-hard X-ray data from GOALS LIRGs (Koss+, 2013)
J/ApJS/206/1 : Mid-IR properties of GOALS nearby LIRGs (Stierwalt+, 2013)
J/PASJ/65/113 : 0.006≤z≤0.8 IR galaxies with AKARI (Toba+, 2013)
J/PASJ/65/103 : PAH3.3um/IR luminosity for infrared galaxies (Yamada+, 2013)
J/ApJ/790/124 : Dust and gas physics of the GOALS sample (Stierwalt+, 2014)
J/ApJ/799/10 : Arp 220 6 and 33GHz images (Barcos-Munoz+, 2015)
J/A+A/574/A4 : Radio image of Luminous Infrared Galaxies (Vardoulaki+, 2015)
J/A+A/590/A67 : Ionized gas maps of local U/LIRGs (Piqueras-Lopez+, 2016)
J/ApJS/229/25 : GOALS sample PACS and SPIRE fluxes (Chu+, 2017)
J/ApJ/846/32 : Herschel FIR spectra of GOALS galaxies (Diaz-Santos+, 2017)
J/ApJ/843/91 : Massive star cluster in LIRGs in GOALS. (Linden+, 2017)
J/ApJ/836/185 : SED radio continuum from KINGFISHER (Tabatabaei+, 2017)
J/A+A/617/A130 : Luminous infrared galaxies AKARI 2.5-5um data (Inami+, 2018)
J/A+A/609/A9 : Local Swift-BAT AGN observed with Herschel (Lutz+, 2018)
J/ApJS/234/24 : VLA 33GHz obs. of star-forming regions (Murphy+, 2018)
J/A+A/623/A173 : SNe/SNRs in starburst galaxy Arp 220 (Varenius+, 2019)
J/ApJ/882/5 : ALMA data for 5 luminous & ultralum. IR gal. (Wilson+, 2019)
J/ApJ/888/92 : Star-forming clumps in local luminous IR gal. (Larson+, 2020)
J/ApJS/248/25 : SFRS: 3-33GHz VLA obs. of star-forming regions (Linden+, 2020)
J/ApJ/923/278 : Massive star cluster in LIRGs in GOALS. II. (Linden+, 2021)
J/A+A/660/A83 : NGC1068 I-HCN(1-0) & I-HCO+(1-0) maps (Sanchez-Garcia+, 2022)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- ID [1/68] Internal index number
4- 14 A11 --- IRAS IRAS system identifier
16- 35 A20 --- Gal Common galaxy Name
37- 38 I2 h RAh Hour of Right Ascension (J2000) (1)
40- 41 I2 min RAm Minute of Right Ascension (J2000) (1)
43- 47 F5.2 s RAs Second of Right Ascension (J2000) (1)
49 A1 --- DE- Sign of the Declination (J2000) (1)
50- 51 I2 deg DEd Degree of Declination (J20000 (1)
53- 54 I2 arcmin DEm Arcminute of Declination (J2000) (1)
56- 59 F4.1 arcsec DEs Arcsecond of Declination (J2000) (1)
61- 65 F5.2 [Lsun] logLIR [11/12.5] log 8-1000 micron IR luminosity
67- 71 I5 km/s HVel [1137/26249] Heliocentric velocity from NED
73- 75 I3 Mpc Dist [17/401] Luminosity distance
77- 80 I4 pc/arcsec Scale [80/1643] Physical scale (2)
82 A1 --- Stage Merger stage (3)
--------------------------------------------------------------------------------
Note (1): Based on Spitzer IRAC 8 micron imaging (Mazzarella, in prep.;
Chu+ 2017, J/ApJS/229/25).
Note (2): Corresponding to 1" at the distance of the system, calculated
using the 3-attractor model (Mould 2000ApJ...529..786M 2000ApJ...529..786M)
and Ned Wright's Cosmology Calculator (Wright 2006PASP..118.1711W 2006PASP..118.1711W),
based on positions and velocities.
Note (3): Based on visual classification from Stierwalt+ (2013, J/ApJS/206/1);
code as follows:
a = pre-merger (18 occurrences)
b = early-merger (10 occurrences)
c = mid-merger (4 occurrences)
d = late-merger (21 occurrences)
N = isolated galaxy (15 occurrences)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- ID [1/67] Internal index number
4 A1 --- f_ID Flag on ID (1)
5 A1 --- n_ID [b] b: flag on Arp 240 region (2)
7- 9 A3 --- Reg Region identifier (3)
11- 19 A9 --- Type Region type (4)
21- 30 F10.6 deg RAdeg Right Ascension (J2000) (5)
32- 41 F10.6 deg DEdeg [-19.1/19.6] Declination (J2000) (5)
43- 47 F5.2 mJy Snu [0.01/31] Measured 33 GHz flux
density of region (6)
49- 52 F4.2 mJy e_Snu [0/0.3] Uncertainty in Snu
54 A1 --- l_logRe Limit flag on logRe (7)
55- 59 F5.2 [pc] logRe [0.9/2.3] Log Region effective
radius
61- 64 F4.2 [pc] e_logRe [0/0.5]? Uncertainty in logRe
66- 70 F5.2 [10-7W/Hz] logLnu [26.25/29.53] Log spectral
luminosity
72- 75 F4.2 [10-7W/Hz] e_logLnu [0.01/0.9] Uncertainty in logLnu
77 A1 --- l_logSigma Limit flag on logSigma (7)
79- 83 F5.2 [10-7W/Hz/kpc2] logSigma [28.4/31.6] Log spectral luminosity
surface density
85- 88 F4.2 [10-7W/Hz/kpc2] e_logSigma [0/1.2]? Uncertainty in logSigma
90 A1 --- l_logTb Limit flag on logTb (7)
91- 95 F5.2 [K] logTb [-0.12/3.1] Log brightness
temperature of region (8)
97- 100 F4.2 [K] e_logTb [0.01/1.2]? Uncertainty in logTb
102 A1 --- l_logTim Limit flag on logTim (7)
103- 107 F5.2 [K] logTim [-0.31/4.1]? Log brightness
temperature of region (9)
109- 112 F4.2 [K] e_logTim [0.01/1.3]? Uncertainty in logTim
--------------------------------------------------------------------------------
Note (1): Flag as follows:
* = for this system, 15GHz measurements are reported, due to either
non- or poor detection (SNR<5) at 33GHz. For all other
regions, 33GHz measurements are used (i.e. ν=33).
Note (2): Note as follows:
b = We note that in Arp240 (NGC5257/8), regions in NGC5258 were only
detected at 15GHz.
Note (3): Identifier for regions within each IRAS system identified and
characterized using Astrodendro, with "nuclear" and "off-nuclear"
regions labeled with "n" and "extra-nuclear" regions labeled
with "e". Regions within each system are numbered following the
order of ascending declination.
Note (4): Region type as follows:
SF = star-forming clump (50 occurrences)
AGN/SBnuc = AGN-starburst composite nucleus (32 occurrences)
AGN = Active galactic nuclei (16 occurrences)
Jet = AGN jet (9 occurrences)
SBnuc = starburst nucleus (8 occurrences)
Bg = background radio source; see note on IC 0214 in Appendix A
(1 occurrence)
Ud = unsure (17 occurrences)
Note (5): Coordinates of the emission peak of the region
Note (6): Note the flag on the ID indicating sources with 15GHz measurements.
Note (7): For unresolved regions smaller than the synthesized beam accounting
for uncertainties, these are reported as limits for the region.
Note (8): Derived using Astrodendro measurements.
Note (9): Derived via Gaussian-fitting using CASA imfit
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- ID [1/67] Internal index number
4- 5 A2 --- f_ID Flag on ID (1)
7- 17 A11 --- Reg Region identifier(s) (2)
19- 27 A9 --- Type Region type (3)
29 A1 --- l_S33 Limit flag on S33
31- 35 F5.2 mJy S33 [0.01/26.6] Measured 33GHz flux
of beam-matched region (4)
37- 40 F4.2 mJy e_S33 [0.01/3.1]? Uncertainty in S33
42- 46 F5.2 mJy S15 [0.02/60.3] Measured 15GHz flux
of beam-matched region
48- 51 F4.2 mJy e_S15 [0.01/6] Uncertainty in S15
53 A1 --- l_alpha Limit flag on alpha
54- 59 F6.2 --- alpha [-2.61/1.4] Measured 15-33GHz
spectral index of beam-matched
region
61- 64 F4.2 --- e_alpha [0.18/5.32]? Uncertainty in alpha
66 A1 --- l_fth Limit flag on fth
68- 70 I3 % fth [0/100] Thermal fraction at 33GHz
derived from alpha
72- 73 I2 % e_fth [4/46]? Uncertainty in fth
75 A1 --- l_logRe Limit flag on logRe
76- 80 F5.2 pc logRe [0.89/2.5] Log Region effective
radius (5)
82- 85 F4.2 pc e_logRe [0.01/0.21]? Uncertainty in logRe
87- 91 F5.2 [Msun/yr] logSFR [-0.9/1.11]? Log Star Formation
Rate (6)
93- 96 F4.2 [Msun/yr] e_logSFR [0.03/1.1]? Uncertainty in logSFR
98 A1 --- l_logSigma Limit flag on logSigma
99- 103 F5.2 [Msun/yr/kpc2] logSigma [1.1/3.2]? Log star formation rate
surface density
105- 108 F4.2 [Msun/yr/kpc2] e_logSigma [0.04/0.5]? Uncertainty in
logSigma
110 A1 --- l_logSFRth Limit flag on logSFRth
111- 116 F6.2 [Msun/yr] logSFRth [-1.4/1.1]? Log thermal only star
formation rate
118- 121 F4.2 [Msun/yr] e_logSFRth [0.07/1.4]? Uncertainty in log
SFRth
123 A1 --- l_logSigmath Limit flag on logSigmath
124- 128 F5.2 [Msun/yr/kpc2] logSigmath [0/3.3]? Log thermal only star
formation rate surface density
130- 133 F4.2 [Msun/yr/kpc2] e_logSigmath [0.07/1.4]? Uncertainty in
logSigmath
--------------------------------------------------------------------------------
Note (1): For systems marked with "*", 15 GHz measurements are reported, due
to either non- or poor detection (SNR<5) at 33GHz. For all other
regions, 33GHz measurements are used (i.e. ν=33).
We note that in Arp240 (NGC5257/8), regions in NGC5258 were only
detected at 15 GHz which is flagged with "b".
Note (2): Corresponding to the same column in Table 2.
Note (3): The most likely source for the detected radio emission.
See Section 4.1 and Appendix A for details.
Note (4): For regions identified at 15GHz, upper-limits on the 33GHz flux
densities are provided.
Note (5): Based on region area (A) computed by Astrodendro, defined as
Re = sqrt(A/π). For unresolved regions that are smaller than the
matched-beam accounting for uncertainties, the effective radius of
the matched-beam is reported instead as an upper-limit for
the region size.
Note (6): Derived from either 33 GHz or 15 GHz flux densities.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- Gal Galaxy name
17- 18 A2 --- Reg Region within Gal (1)
20- 25 A6 --- Type Region type (2)
27- 36 F10.6 deg RAdeg [135.1/354.8] Right ascension of
the emission peak of the region
(J2000)
38- 46 F9.6 deg DEdeg [23.5/62.2] Declination of the
emission peak of the region
(J2000)
48- 51 F4.2 pc logRe [1.25/2.6] Log of region
effective radius
53- 56 F4.2 pc e_logRe [0.01/0.12] logRe uncertainty
58- 62 F5.2 mJy S33 [0.14/74.7] 33GHz flux density
64- 67 F4.2 mJy e_S33 [0.01/5] S33 uncertainty
69- 73 F5.2 [10-7W/Hz] logL33 [27.3/30.52] Log of 33GHz
spectral luminosity calculated
from S33
75- 78 F4.2 [10-7W/Hz] e_logL33 [0.01/0.1] logL33 uncertainty
80- 84 F5.2 [10-7W.Hz-1/kpc2] logSigL33 [29.42/31.26] 33 GHz spectral
luminosity surface density,
calculated from columns logRe
and logL33
86- 89 F4.2 [10-7W.Hz-1/kpc2] e_logSigL33 [0.01/0.24] logSigL33 uncertainty
--------------------------------------------------------------------------------
Note (1): Region identifier including galaxy name, with "n" and "e" indicating
region location:
n = within the MIR galaxy core measured by Diaz-Santos+ (2010, J/ApJ/723/993)
e = extranuclear (outside MIR galaxy core)
Note (2): Region type indicating the most likely source for the detected
radio emission, classified following Section 4.1.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Gal Common galaxy name
8 A1 --- --- [_]
9- 11 A3 --- Reg Region identifier within
the galaxy (1)
13- 21 F9.5 deg RAdeg [14.95/309] Right Ascension (J2000)
23- 31 F9.5 deg DEdeg [-33.1/68.5] Declination (J2000)
33 A1 --- l_logRe Limit flag on logRe
34- 38 F5.2 pc logRe [1.19/2.61] Log Region effective
radius (2)
40- 43 F4.2 pc e_logRe [0.01/0.11]? Uncertainty in logRe
45- 49 F5.2 mJy S15 [0.01/19.4] Measured 15GHz flux
density
51- 54 F4.2 mJy e_S15 [0.01/2] Uncertainty in S15
56- 60 F5.2 mJy S33 [0.01/12.7] Measured 33GHz flux
density
62- 65 F4.2 mJy e_S33 [0.01/1.3] Uncertainty in S33
67- 71 F5.2 --- alpha [-1.03/2.24] Measured 15-33GHz
spectral index
73- 76 F4.2 --- e_alpha [0.18/4.5] Uncertainty in alpha
78- 80 I3 % fth [14/100] Thermal fraction
at 33GHz (3)
82- 83 I2 % e_fth [2/64]? Uncertainty in fth
85- 89 F5.2 [Msun/yr] logSFR [-3.31/-0.27] Log Star Formation
Rate (4)
91- 94 F4.2 [Msun/yr] e_logSFR [0.02/0.4] Uncertainty in logSFR
96 A1 --- l_logSigma Limit flag on logSigma
97- 101 F5.2 [Msun/yr/kpc2] logSigma [-1.53/1] Log star formation
rate surface density (5)
103- 106 F4.2 [Msun/yr/kpc2] e_logSigma [0.05/0.4]? Uncertainty in
logSigma
108- 112 F5.2 [Msun/yr] logSFRth [-3.5/-0.27] Log thermal only
star formation rate (6)
114- 117 F4.2 [Msun/yr] e_logSFRth [0.08/1.72] Uncertainty in
logSFRth
119 A1 --- l_logSigmath Limit flag on logSigmath
120- 124 F5.2 [Msun/yr/kpc2] logSigmath [-1.9/1.1] Log thermal only star
formation rate surface density (5)
126- 129 F4.2 [Msun/yr/kpc2] e_logSigmath [0.08/1.3]? Uncertainty in
logSigmath
--------------------------------------------------------------------------------
Note (1): Indicating the location of the region within the galaxy:
n = nuclear (within 250pc of the galaxy center),
e = extra-nuclear.
Note (2): For regions with area smaller than the matched 15 - 33GHz synthesized
beam (i.e. unresolved), the effective radius of the synthesized beam
is reported and marked as upper-limits
Note (3): Estimated from S33 using Equation 4.
Note (4): Derived from total 33GHz continuum emission from S33 using Equation 5.
Note (5): For unresolved regions, the reported values are lower-limits.
Note (6): Derived from 33GHz flux in column S33 and alpha in column alpha,
using Equation 6.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Oct-2024