J/AJ/163/16 Multiwavelength study in M33 star clusters (Moeller+, 2022)
Ages and Masses of Star Clusters in M33; a Multiwavelength Study.
Moeller C., Calzetti D.
<Astron. J., 163, 16 (2022)>
=2022AJ....163...16M 2022AJ....163...16M
ADC_Keywords: Clusters, open; Stars, ages; Stars, masses; Photometry, UBVRI
Keywords: Young star clusters
Abstract:
We combine archival images for the nearby galaxy M33 (Triangulum
Galaxy) from the ultraviolet (UV) to the infrared to derive ages,
masses, and extinctions for the young star cluster population, and
compare our physical parameters with published ones. Our goal is to
test the robustness of clusters ages and masses, and possibly improve
on existing ones both by expanding the wavelength range of the
spectral-energy distribution (SED) fits and by using more recent
population synthesis models. The rationale for this experiment is to
verify the sensitivity of the clusters physical parameters to
observational setups and model choices that span those commonly found
in the literature. We derive the physical parameters of 137 clusters,
using SEDs measured in eight UV-to-I bands, including Hα, from
GALEX and ground-based images. We also add the 24µm image from the
Spitzer Space Telescope to help break some age degeneracies. We find
that our derived cluster ages show significant differences with
earlier determinations, while the masses remain relatively insensitive
to the fitting approach adopted. We also highlight an already known
difficulty in recovering old, low-extinction clusters, as SED-fitting
codes tend to prefer younger, higher extinction solutions when the
extinction is a free parameter. We publish updated ages, masses, and
extinctions, with uncertainties for all sample star clusters, together
with their photometry. Given the proximity of M33, this represents an
important population to secure for the study of star formation and
cluster evolution in spirals.
Description:
Ultraviolet, optical and infrared (IR) images from a combination of
space and ground-based imaging data of the M33 galaxy were retrieved
from NED, for a total of 10 bands: far-UV (FUV), near-UV (NUV), U, B,
V, R, I, Hα (6563Å), 3.6µm, and 24µm. The Galaxy
Evolution Explorer (GALEX) satellite observed M33 in both the FUV and
NUV channels with a single pointing of its ∼1.6degx1.6deg
field-of-view (FoV) with angular resolution ∼4"-5". The optical band
images were obtained at the Mayall 4m telescope at Kitt Peak National
Observatory (KPNO), with the Mosaic Camera, with a 38'x38' FoV and
angular resolution between 0.8" and 1". To observe the entirety of
M33, images were taken in three different pointings: Northern,
Central, and Southern. Mosaics at the wavelengths 3.6µm and 24µm
were obtained with the Spitzer Space Telescope Infrared Array Camera
(IRAC) and Multi-Band Imaging Photometer (MIPS) cameras, respectively,
with angular resolutions of 1.7" at 3.6µm and 6.5" at 24µm.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 106 163 *Photometric measurements of the M33 star clusters
table4.dat 170 26 Clusters excluded from analysis
table6.dat 261 137 Derived and literature physical properties of the
M33 star clusters
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Note on table3.dat: The flux densities for the UV and optical bands
are reported as directly measured, i.e., no correction for the
foreground Milky Way extinction has been applied.
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See also:
J/A+AS/141/371 : Low-mass stars evolut. tracks & isochrones (Girardi+, 2000)
J/ApJ/633/871 : Positions and photometry of HII knots in M51 (Calzetti+, 2005)
J/AJ/131/2478 : M31 and M33 UBVRI photometry (Massey+, 2006)
J/AJ/134/2474 : Hα emission-line stars 7 dwarfs galaxies (Massey+, 2007)
J/ApJ/658/1006 : Radial profiles for 161 face-on spirals (Munoz-Mateos+, 2007)
J/AJ/134/447 : Catalog of star cluster candidates in M 33 (Sarajedini+, 2007)
J/ApJS/178/247 : Hα and [NII] survey in local 11 Mpc (Kennicutt+, 2008)
J/ApJ/706/553 : Fluxes in nearby star-forming galaxies (Boquien+, 2009)
J/ApJ/703/517 : The Spitzer Local Volume Legacy: IR photometry (Dale+, 2009)
J/A+A/534/A96 : Spitzer photometry of YSC in M33 (Sharma+, 2011)
J/ApJ/812/147 : Slug analysis star clusters in NGC628 & 7793 (Krumholz+, 2015)
J/ApJ/824/71 : Compact star clusters in M51 with HST (Chandar+, 2016)
J/ApJ/841/92 : Young massive star clusters in 2 LEGUS galaxies (Ryon+, 2017)
J/ApJ/889/154 : LEGUS & Ha-LEGUS obs. NGC4449 star clusters (Whitmore+, 2020)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- SM2007 [9/439] Identifier from
Sarajedini+, 2007, J/AJ/134/447
5- 7 I3 --- ID [0/162] Identifier, from this work
9- 9 A1 --- l_FUV Limit flag on S-FUV
11- 19 E9.3 10+7W/m3 FUV FUV Flux density, erg/s/cm2/Angstrom
21- 21 A1 --- l_NUV Limit flag on S-NUV
23- 31 E9.3 10+7W/m3 NUV NUV Flux density, erg/s/cm2/Angstrom
33- 40 E8.2 10+7W/m3 FluxU U-band flux density, erg/s/cm2/Angstrom
42- 49 E8.2 10+7W/m3 FluxB B-band flux density, erg/s/cm2/Angstrom
51- 58 E8.2 10+7W/m3 FluxV V-band flux density, erg/s/cm2/Angstrom
60- 67 E8.2 10+7W/m3 FluxR R-band flux density, erg/s/cm2/Angstrom
69- 76 E8.2 10+7W/m3 FluxHa Hα flux density, erg/s/cm2/Angstrom
78- 85 E8.2 10+7W/m3 FluxI I-band flux density, erg/s/cm2/Angstrom
87- 95 E9.3 10-3W/m2 Flux3.6 3.6um flux, erg/s/cm2
97- 97 A1 --- l_Flux24 Limit flag on F-24
99-106 E8.2 10-3W/m2 Flux24 24um flux, erg/s/cm2
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- SM2007 [44/419] Identifier from
Sarajedini+, 2007, J/AJ/134/447
5- 7 I3 --- ID [7/155] Identifier, this work
9- 10 I2 h RAh [01] Hour of Right Ascension (J2000)
12- 13 I2 min RAm [33/34] Minute of Right Ascension (J2000)
15- 19 F5.2 s RAs Second of Right Ascension (J2000)
21- 21 A1 --- DE- [+] Sign of the Declination (J2000)
22- 23 I2 deg DEd [30] Degree of Declination (J2000)
25- 26 I2 arcmin DEm [21/58] Arcminute of Declination (J2000)
28- 31 F4.1 arcsec DEs Arcsecond of Declination (J2000)
33- 37 F5.2 [yr] Age [6.6/10.3] log Age, Sarajedini+, 2007, J/AJ/134/447
39- 42 F4.2 [Msun] Mass [2.62/5.57] log Mass,
Sarajedini+, 2007, J/AJ/134/447
44-170 A127 --- Comm Comments
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- SM2007 [9/439] Identifier from
Sarajedini+, 2007, J/AJ/134/447
5- 7 I3 --- ID [0/162] Identifier, this work
9- 10 I2 h RAh [01] Hour of Right Ascension (J2000)
12- 13 I2 min RAm [32/34] Minute of Right Ascension (J2000)
15- 19 F5.2 s RAs Second of Right Ascension (J2000)
21- 21 A1 --- DE- [+] Sign of the Declination (J2000)
22- 23 I2 deg DEd [30] Degree of Declination (J2000)
25- 26 I2 arcmin DEm [03/58] Arcminute of Declination (J2000)
28- 32 F5.1 arcsec DEs Arcsecond of Declination (J2000)
34- 38 F5.2 [yr] AgeSM [6.52/10.3] log Age,
Sarajedini+, 2007, J/AJ/134/447
40- 44 F5.2 [yr] Age [6.3/10.1] log Age, this work
46- 49 F4.2 [yr] e_Age [0/3] Uncertainty (1σ) in Age
51- 54 F4.2 [Msun] MassSM [2.31/6.27] log Mass,
Sarajedini+, 2007, J/AJ/134/447
56- 59 F4.2 [Msun] Mass [2/5.32] log Mass, this work
61- 65 F5.3 [Msun] e_Mass [0.004/0.1] Uncertainty (1σ) in Mass
67- 70 F4.2 mag E(B-V) [0/0.66] Reddening (1)
72- 75 F4.2 mag e_E(B-V) [0.01/0.22] Uncertainty in E(B-V)
77-261 A185 --- Comm ?=--- Comments (2)
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Note (1): The E(B-V) values in this Table are the sum of the internal dust
reddening in the star cluster plus the foreground reddening of the Milky
Way, E(BV)=0.036 (Schlafly & Finkbeiner, 2011ApJ...737..103S 2011ApJ...737..103S).
Note (2): In some instances of two or more sources present in the aperture,
the best fit results are retained if the sources appear of comparable
age (similar behavior in colors), as indicated in the Comments field; in
this case, the quoted mass is the sum of all masses for the sources in
the aperture. For sources yielding with two best-fits to the
age/extinction, the reported value reflects an assessment based on the
24um emission. The retained best fit is given in the Comments field.
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History:
From electronic version of the journal
09-Jun-2022: new version of table6.dat, the original one contained
erroneous degrees of declination corrected by the author.
Acknowledgment:
Caitlin Moeller
(End) Prepared by [AAS], Coralie Fix [CDS], 28-Mar-2022