J/MNRAS/431/2917 NGC5253 star clusters age and mass (de Grijs+, 2013)
The NGC 5253 star cluster system.
I. Standard modelling and infrared-excess sources.
de Grijs R., Anders P., Zackrisson E., Ostlin G.
<Mon. Not. R. Astron. Soc., 431, 2917-2932 (2013)>
=2013MNRAS.431.2917D 2013MNRAS.431.2917D
ADC_Keywords: Galaxies, nearby ; Associations, stellar
Keywords: methods: data analysis - stars: luminosity function, mass function -
galaxies: starburst - galaxies: star clusters: general -
infrared: galaxies
Abstract:
Using high-resolution Hubble Space Telescope data, we re-examine the
fundamental properties (ages, masses and extinction values) of the
rich star cluster population in the dwarf starburst galaxy NGC 5253.
The gain in resolution compared to previous studies is of order a
factor of 2 in both spatial dimensions, while our accessible
wavelength range transcends previous studies by incorporation of both
near-ultraviolet and near-infrared (IR) passbands. We apply spectral
synthesis treatments based on two different simple stellar population
model suites to our set of medium-, broad-band and Hα images to
gain an improved physical understanding of the IR-excess flux found
for a subset of young clusters (30 of 149). With the caveat that our
models are based on fully sampled stellar mass functions, the NGC 5253
cluster population is dominated by a significant number of relatively
low-mass (Mcl≲ a few x104M☉) objects with ages ranging from
a few x106 to a few x107yr, which is in excellent agreement with
the starburst age of the host galaxy. The IR-excess clusters are
almost all found in this young age range and have masses of up to a
few x104M☉. The IR excess in the relatively low-mass NGC 5253
clusters is most likely caused by a combination of stochastic sampling
effects and colour variations due to the presence of either luminous
red or pre-main-sequence stars. We also find a small number of
intermediate-age (∼1Gyr old), ∼105M☉ clusters, as well as up to
a dozen massive, ∼10Gyr old globular clusters. Their presence supports
the notion that NGC 5253 is a very active galaxy that has undergone
multiple episodes of star cluster formation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 67 182 NGC 5253 cluster coordinates and derived parameters
assuming fully sampled YGGDRASIL SSP models
(Zackrisson et al. 2011ApJ...740...13Z 2011ApJ...740...13Z)
table3.dat 34 182 NGC 5253 cluster parameters derived assuming
fully sampled GALEV SSP models (Kotulla et al.
2009MNRAS.396..462K 2009MNRAS.396..462K)
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See also:
J/ApJ/603/503 : HST photometry in NGC 5253 and NGC 3077 (Harris+, 2004)
J/ApJ/656/168 : Spectrophotometry in NGC 5253 (Lopez-Sanchez+, 2007)
J/A+A/550/A88 : Data cubes of NGC 5253 (476-682nm) (Westmoquette+, 2013)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [0/182] Cluster identification number
5- 15 F11.7 deg RAdeg Right ascension (J2000)
17- 27 F11.7 deg DEdeg Declination (J2000)
29- 33 F5.3 pix Size Gaussian sigma σG(F550M)
35- 36 I2 --- Nf [7/10]?=- Number of filters used to obtain
the derived parameters
38- 42 F5.2 [yr] logt1 [6.0/10.2]?=- log of the best age (YGGDRASIL)
44- 47 F4.2 [yr] E_logt1 ?=- Error on logt (upper value)
49- 52 F4.2 [yr] e_logt1 ?=- Error on logt (lower value)
54- 57 F4.2 [Msun] logM1 [2.4/5.7]?=- log of the best mass (YGGDRASIL)
59- 62 F4.2 [Msun] E_logM1 ?=- Error on logM (upper value)
64- 67 F4.2 [Msun] e_logM1 ?=- Error on logM (lower value)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [0/182] Cluster identification number
5- 9 F5.2 [yr] logt2 [6.6/10.1]?=- log of the best age (GALEV)
11- 14 F4.2 [yr] E_logt2 ?=- Error on logt2 (upper value)
16- 19 F4.2 [yr] e_logt2 ?=- Error on logt2 (lower value)
21- 24 F4.2 [Msun] logM2 [2.3/5.0]?=- log of the best mass (GALEV)
26- 29 F4.2 [Msun] E_logM2 ?=- Error on logM2 (upper value)
31- 34 F4.2 [Msun] e_logM2 ?=- Error on logM2 (lower value)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 17-Jun-2014