J/MNRAS/426/2427 Structural parameters of M33 star clusters (San Roman+, 2012)
Newly identified star clusters in M33. III. Structural parameters.
San Roman I., Sarajedini A., Holtzman J.A., Garnett D.R.
<Mon. Not. R. Astron. Soc., 426, 2427-2440 (2012)>
=2012MNRAS.426.2427S 2012MNRAS.426.2427S
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Morphology
Keywords: galaxies: individual: M33 - galaxies: spiral -
galaxies: star clusters: general - galaxies: stellar content
Abstract:
We present the morphological properties of 161 star clusters in M33
using the Advanced Camera for Surveys Wide Field Channel on-board the
Hubble Space Telescope using observations with the F606W and F814W
filters. We obtain, for the first time, ellipticities, position angles
and surface brightness profiles for a significant number of clusters.
On average, M33 clusters are more flattened than those of the Milky
Way (MW) and M31, and more similar to clusters in the Small Magellanic
Cloud (SMC). The ellipticities do not show any correlation with age or
mass, suggesting that rotation is not the main cause of elongation in
the M33 clusters.
Description:
The observations and data reduction for the present study are
described in a companion paper (San Roman et al. 2009ApJ...699..839S 2009ApJ...699..839S,
Cat. J/ApJ/699/839, hereafter Paper I), and for a detailed description
we refer the reader to that paper. For convenience, we provide an
abbreviated summary below.
The observations were obtained with the Advanced Camera for Surveys
(ACS) Wide Field Channel on-board the HST. 12 HST/ACS fields from the
GO-10190 programme (PI: D. Garnett) have been analysed. Three filters
were used for the primary observations (F475W, F606W, F814W) and two
for the parallel images (F606W, F814W). The fields are located along
the south-west direction covering a radial extension between 0.9 and
6.6kpc from the centre of the galaxy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 161 Ellipticities and position angles
table2.dat 107 256 Structural parameters from the King profile fit
table3.dat 88 256 Structural parameters from the EFF profile fit
(Elson-Freeman-Fall, 1987ApJ...323...54E 1987ApJ...323...54E)
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See also:
J/ApJ/720/1674 : CFHT M33 extended sources catalog (San Roman+, 2010)
J/ApJ/699/839 : Newly identified star clusters in M33. II. (San Roman+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/161] Running cluster identification number
(<[SSG2009] NNN> in Simbad)
ID (Identification number in Paper II)
5- 8 F4.2 --- eF606W ?=- Ellipticity [F606W]
10- 13 F4.2 --- e_eF606W ?=- Uncertainty in eF606W
15- 18 F4.2 --- eF814W ?=- Ellipticity [F814W]
20- 23 F4.2 --- e_eF814W ?=- Uncertainty eF814W
25- 29 F5.1 deg PAF606W ?=- Position Angle [F606W]
31- 34 F4.1 deg e_PAF606W ?=- Uncertainty in PAF606W
36- 40 F5.1 deg PAF814W ?=- Position Angle [F814W]
42- 45 F4.1 deg e_PAF814W ?=- Uncertainty in PAF814W
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/161] Running cluster identification number
5- 9 A5 --- Filt Filter (F606W or F814W)
11- 15 F5.2 mag/arcsec2 mu0 ?=- Central surface brightness in filter (1)
17- 20 F4.2 mag/arcsec2 e_mu0 ?=- Uncertainty in mu0
22- 25 F4.2 arcsec Rc Core radius in filter in arcsec (1)
27- 30 F4.2 arcsec e_Rc Uncertainty in Rc
32- 35 F4.2 pc Rc1 Core radius in filter in pc
37- 40 F4.2 pc e_Rc1 Uncertainty in Rc1
42- 46 F5.2 arcsec Rt ?=- Tidal radius in filter in arcsec (1)
48- 51 F4.2 arcsec e_Rt ?=- Uncertainty in Rt
53- 57 F5.2 pc Rt1 ?=- Tidal radius in filter in pc
59- 63 F5.2 pc e_Rt1 ?=- Uncertainty in Rt1
65- 68 F4.2 --- c ?=- Concentration in filter
70- 73 F4.2 --- e_c ?=- Uncertainty in c
75- 78 F4.2 arcsec Rh ?=- Half-light radius in filter in arcsec
80- 83 F4.2 arcsec e_Rh ?=- Uncertainty in Rh
85- 88 F4.2 pc Rh1 ?=- Half-light radius in filter in pc
90- 93 F4.2 pc e_Rh1 ?=- Uncertainty in Rh1
95-101 F7.2 Lsun/pc+2 Int Background intensity in filter
103-107 F5.2 Lsun/pc+2 e_Int Uncertainty in Int
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Note (1): the King model parametrizes the surface brightness as
µ(r)=µ0.[1/sqrt(1+(r/Rc)2)-1/sqrt(1+(Rt/Rc)2)]2
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [1/161] Running cluster identification number
5- 9 A5 --- Filt Filter (F606W or F814W)
11- 15 F5.2 mag/arcsec2 mu0 ?=- Central surface brightness in filter (1)
17- 21 F5.2 mag/arcsec2 e_mu0 ?=- Uncertainty in mu0
23- 26 F4.2 arcsec a ?=- Scale radius in filter in arcsec (1)
28- 31 F4.2 arcsec e_a ?=- Uncertainty in a
33- 36 F4.2 pc a1 ?=- Scale radius in filter in pc
38- 41 F4.2 pc e_a1 ?=- Uncertainty in a1
43- 47 F5.2 --- gamma ?=- Power-law slope γ at large radii
in filter (1)
49- 53 F5.2 --- e_gamma ?=- Uncertainty in gamma
55- 58 F4.2 arcsec Rh ?=- Half-light radius in filter in arcsec
60- 63 F4.2 arcsec e_Rh ?=- Uncertainty in Rh
65- 69 F5.2 pc Rh1 ?=- Half-light radius in filter in pc
71- 74 F4.2 pc e_Rh1 ?=- Uncertainty in Rh1
76- 82 F7.2 Lsun/pc+2 Int ?=- Background intensity in filter
84- 88 F5.2 Lsun/pc+2 e_Int ?=- Uncertainty in Int
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Note (1): the EFF model parametrizes the surface brightness as
µ(r) = µ0.(1+(r/a)2)-γ/2
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History:
From electronic version of the journal
References:
San Roman et al., Paper I 2010ApJ...720.1674S 2010ApJ...720.1674S, Cat. J/ApJ/720/1674
San Roman et al., Paper II 2009ApJ...699..839S 2009ApJ...699..839S, Cat. J/ApJ/699/839
(End) Patricia Vannier [CDS] 24-Apr-2013