J/MNRAS/442/1049 HST gz magnitude of NGC 1023 star clusters (Forbes+, 2014)
Extended star clusters in NGC 1023 from HST/ACS mosaic imaging.
Forbes D.A., Almeida A., Spitler L.R., Pota V.
<Mon. Not. R. Astron. Soc., 442, 1049-1053 (2014)>
=2014MNRAS.442.1049F 2014MNRAS.442.1049F
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Photometry, HST
Keywords: galaxies: evolution - galaxies individual: NGC 1023 -
galaxies: star clusters: general
Abstract:
Faint fuzzies (FFs) are a relatively new class of star cluster, first
found in the nearby S0 galaxy NGC 1023 by Larsen & Brodie
(2000AJ....120.2938L 2000AJ....120.2938L) using Wide Field Planetary Camera 2 (WFPC2)
images from the Hubble Space Telescope (HST). Here, we investigate the
star cluster system of NGC 1023 using an eight pointing mosaic of
Advanced Camera for Surveys (ACS) images from HST. We identify blue
and red normal globular clusters (two of which are particularly
luminous and dense) and two ultracompact dwarf objects (with effective
radius ∼10pc). With our more complete spatial coverage, we also find
81 red and 27 blue FFs. We confirm the association of the red FFs with
the disc of NGC 1023, consistent with them being long-lived open
clusters. Half of the blue FFs appear to be associated with the dwarf
satellite galaxy NGC 1023A (which was largely absent from the original
HST/WFPC2 coverage), while the remainder are spatially coincident with
the densest HI gas that surrounds NGC 1023. The blue FFs have colours
that are consistent with young (few 100Myr old) star clusters that
formed during the most recent interaction between NGC 1023 and its
satellite NGC 1023A.
Description:
The eight HST/ACS F475W (g) and F850LP (z) band images used in this
study were taken as part of proposal 12202 (PI: Sivakoff). Exposure
times were typically 768s in the g band and 1308s in the z band. The
eight images create a rare ACS mosaic of a nearby early-type galaxy,
covering approximately 12x7-arcmin2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 75 358 Star clusters in NGC 1023
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See also:
J/MNRAS/384/943 : Velocities of NGC 1023 planetary nebulae (Noordermeer+, 2008)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Star [1/377] Star cluster identification number
5- 11 F7.4 deg RAdeg Right ascension (J2000)
13- 19 F7.4 deg DEdeg Declination (J2000)
21- 26 F6.3 mag gmag [19.7/25.2] HST g (F475W) magnitude
28- 32 F5.3 mag e_gmag [0.001/0.135] rms uncertainty on gmag
34- 39 F6.3 mag zmag [18.5/23.5] HST z (F850LP) magnitude
41- 45 F5.3 mag e_zmag [0.001/0.217] rms uncertainty on zmag
47- 51 F5.3 mag g-z HST g-z colour index
53- 57 F5.3 mag e_g-z [0.005/0.27] rms uncertainty on g-z
59- 63 F5.2 pc Re [0.3/21] Half-light effective radius
65- 69 F5.2 pc E_Re Error on Re (upper value)
71- 75 F5.2 pc e_Re Error on Re (lower value)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 27-Feb-2015