J/MNRAS/492/993 Super star clusters of M82's disk (Cuevas-Otahola+, 2020)
Structural analysis of disc super star clusters of M82:
size and profile shape at intermediate ages.
Cuevas-Otahola B., Mayya Y.D., Puerari I., Rosa-Gonzalez D.
<Mon. Not. R. Astron. Soc., 492, 993-1007 (2020)>
=2020MNRAS.492..993C 2020MNRAS.492..993C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Optical
Keywords: catalogues - (Galaxy:) globular clusters: general -
galaxies: clusters: general
Abstract:
We present the structural parameters of 99 super star clusters (SSCs)
in the disc of M82. Moffat-EFF, King, and Wilson models were fitted
using a χ2-minimization method to background-subtracted surface
brightness profiles in the F435W (B), F555W (V), and F814W (I) bands
of the Advanced Camera for Surveys (ACS) of the Hubble Space
Telescope. The majority of the SSC profiles are best fitted by the
Moffat-EFF profile. The scale parameter rd and the shape parameter
γ in the three filters are identical within the measurement
errors. The analysed sample is big enough to allow the
characterization of the distributions of core radii Rc and γ.
The obtained distribution of Rc follows a lognormal form, with
centre and σlog(Rc/pc) being 1.73pc and 0.25, respectively.
The γ distribution is also lognormal with centre and
σlog(γ) being 2.88 and 0.08, respectively. M82 is well
known for the absence of current star formation in its disc, with all
disc SSCs older than 50Myr and hardly any cluster older than ∼300Myr.
The derived distributions compare very well with the distributions for
intermediate-age clusters in the Large Magellanic Cloud (LMC), which
is also a low-mass late-type galaxy similar to M82. On the other hand,
the distributions of Rc in both these galaxies are shifted towards
larger values as compared to SSCs of similar age in the giant spiral
galaxy M83. M82 and LMC also span a narrower range of γ values
as compared to that in M83.
Description:
The sample of super star clusters (SSCs) for structural analysis was
selected from the catalogue of M82 disc SSCs from Mayya et al.
(2008ApJ...679..404M 2008ApJ...679..404M, Cat. J/ApJ/679/404), which consists of 393
objects, and is based on the detection of SSCs in the F435W (B), F555W
(V), and F814W (I) bands of the HST/ACS.
We used the same images that were used for cluster detection to
extract SBPs. These images were part of the HST Legacy Survey, which
were made available in reduced form by the Hubble Heritage Team
(Mutchler et al. 2007PASP..119....1M 2007PASP..119....1M). The image scale corresponds to
0.05arcsec/pixel and covers the entire optical extent of M82. Exposure
times were 1600, 1360, and 1360s in filters B, V, and I, respectively.
The zero-point magnitudes in the Vega system were extracted from
Sirianni et al. (2005PASP..117.1049S 2005PASP..117.1049S), with values 25.779, 25.724, and
25.501 for the B, V, and I bands, respectively.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 41 393 Fitting radius and background value for all M82
disc SSCs
tablea1.dat 14 99 Geometrical properties of M82 disc SSCs
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Object identifier from Mayya et al.
(2008ApJ...679..404M 2008ApJ...679..404M, Cat. J/ApJ/679/404)
(DNNN)
6- 14 F9.5 deg RAdeg Right ascension (J2000)
16- 23 F8.5 deg DEdeg Declination (J2000)
25- 26 I2 pix Rip Innermost inflexion point Rip
28- 30 I3 pix R3s ?=-99 Radius at which the cluster surface
brightness is equal to 3 times the
background noise σbg
32- 36 F5.2 mag/arcsec2 mubg Background surface brightness
38- 41 F4.2 mag/arcsec2 e_mubg Error on mubg
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Object identifier from Mayya et al.
(2008ApJ...679..404M 2008ApJ...679..404M, Cat. J/ApJ/679/404)
(DNNN)
6- 9 F4.2 --- Ell Ellipticity
11- 14 I4 deg PA [] Position angle
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 13-Mar-2023