J/AJ/164/183 UVIT photometry of M31 PHAT stellar clusters (Leahy+, 2022)
AstroSat/UVIT Cluster Photometry in the Northern Disk of M31.
Leahy D., Buick M., Leahy C.
<Astron. J., 164, 183 (2022)>
=2022AJ....164..183L 2022AJ....164..183L
ADC_Keywords: Star Forming Region; Photometry; Ultraviolet; Stars, ages;
Stars, masses
Keywords: Andromeda Galaxy ; Star formation ; Photometry
Abstract:
The Andromeda galaxy (M31) is an object of ongoing study with the
Ultraviolet Imaging Telescope (UVIT) on AstroSat. UVIT far-UV (FUV)
and near-UV (NUV) photometry is carried out here for a set of 239
clusters in the NE disk and bulge of M31 that overlap with the
HST/PHAT survey. Padova stellar models were applied to derive ages,
masses, metallicities, and extinctions for 170 clusters. The ages show
a narrow peak at ∼4Myr and a broad peak around 100Myr. log(Z/Z☉)
values are mostly between -0.3 and +0.3. The 7 clusters in the bulge
have a low metallicity and high mass. Most clusters are in the spiral
arms and have metallicities in the range noted above. The youngest
clusters mostly have high metallicity and are concentrated along the
brightest parts of the spiral arms. The UVIT FUV and NUV data are
sensitive to young stars and detect a new metal-rich peak in star
formation in the disk at age ∼4Myr.
Description:
The Ultraviolet Imaging Telescope (UVIT) M31 survey covers the
Pan-chromatic Hubble Andromeda Treasury (PHAT) region. In the overlap
region, UVIT Fields 1, 2, 7, and 13 have both FUV and NUV
observations, so we chose these four fields for our analysis.
Objects:
--------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------
00 42 44.33 +41 16 07.5 M31 = PLX 124.00
--------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 77 239 UVIT photometry of M31 PHAT stellar clusters
table2.dat 51 170 UVIT-PHAT stellar cluster properties
--------------------------------------------------------------------------------
See also:
J/ApJ/663/320 : IR-through-UV extinction curve (Fitzpatrick+, 2007)
J/ApJS/215/9 : PHAT X. UV-IR photometry of M31 stars (Williams+, 2014)
J/ApJ/802/127 : PHAT stellar cluster survey. II. AP catalog (Johnson+, 2015)
J/ApJ/827/33 : PHAT. XVI. Star cluster masses and ages (Johnson+, 2016)
J/ApJ/846/145 : PHAT. XIX. Formation history of M31 disk (Williams+, 2017)
J/A+A/618/A156 : Stellar populations of central region of M31 (Saglia+, 2018)
J/ApJS/250/23 : AstroSat/UVIT and Chandra X-ray sources in M31 (Leahy+, 2020)
J/ApJS/247/47 : Ultraviolet survey of M31 with UVIT on AstroSat (Leahy+, 2020)
J/AJ/162/199 : UV photometry of 548 variables stars in M31 (Leahy+, 2021)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- PHAT Source ID from Johnson+, 2015, J/ApJ/802/127 (1)
6 A1 --- Comp Composante name
8- 15 F8.5 deg RAdeg [10/12] Right Ascension (J2000)
17- 24 F8.5 deg DEdeg [41/42] Declination (J2000)
26- 30 F5.2 mag F148W [17.2/23.3]? AstroSat/UVIT F148W AB magnitude
32- 35 F4.2 mag e_F148W [0.02/0.3]? Uncertainty in F148Wmag (2)
37- 41 F5.2 mag F172M [16.8/23.1] AstroSat/UVIT F172M AB magnitude
43- 46 F4.2 mag e_F172M [0.03/0.4] Uncertainty in F172Mmag (2)
48- 52 F5.2 mag F219M [17.2/23.4]? AstroSat/UVIT F219M AB magnitude
54- 57 F4.2 mag e_F219M [0.03/0.4]? Uncertainty in F219Mmag (2)
59- 63 F5.2 mag F169M [17.7/22.8]? AstroSat/UVIT F169M AB magnitude
65- 68 F4.2 mag e_F169M [0.03/0.8]? Uncertainty in F169Mmag (2)
70- 74 F5.3 arcsec Sep [0.003/0.53] Separation (3)
76- 77 I2 --- Reg [1/13] Region
--------------------------------------------------------------------------------
Note (1): Sources measured in multiple fields have an 'A' following their
ID number; these also have no regions
Note (2): Photometry errors are given before inclusion of systematic errors
Note (3): Distance between the UVIT position and the
Johnson+, 2015, J/ApJ/802/127 position
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- PHAT [16/6947] PHAT Source ID
6- 10 F5.1 --- chi2 [1/222] Cluster model fitting χ2 value
12- 16 F5.2 [Sun] logZ [-2.33/0.3] log, metallicity, Solar units
18- 21 F4.2 [Sun] e_logZ [0/1.8] Uncertainty in logZ
23- 26 F4.2 [yr] Age [6.6/9.26] log, Age, yr
28- 31 F4.2 [yr] e_Age [0/0.5] Uncertainty in logAge
33- 36 F4.2 [Msun] Mass [1.74/6.3] log, stellar mass in Solar units
38- 41 F4.2 [Msun] e_Mass [0/0.6] Uncertainty in logM
43- 46 F4.2 mag E(B-V) [0/0.57] Reddening
48- 51 F4.2 mag e_E(B-V) [0/0.3] Uncertainty in E(B-V)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 28-Nov-2022