J/AJ/151/23 HST photometry of stars in HD 97950 (Pang+, 2016)
The gray extinction of the ionizing cluster in NGC 3603 from ultraviolet to
optical wavelengths.
Pang X., Pasquali A., Grebel E.K.
<Astron. J., 151, 23 (2016)>
=2016AJ....151...23P 2016AJ....151...23P (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Clusters, open ; Photometry, HST ; Spectral types ;
Colors ; Extinction
Keywords: dust, extinction - H II regions -
open clusters and associations: individual: NGC 3603 -
stars: massive - stars: winds, outflows
Abstract:
We use photometry in the F220W, F250W, F330W, F435W filters from the
High Resolution Channel of the Advanced Camera for Surveys and
photometry in the F555W, F675W, and F814W filters from the Wide Field
and Planetary Camera 2 aboard the Hubble Space Telescope to derive
individual stellar reddenings and extinctions for stars in the HD97950
cluster in the giant HII region NGC 3603. The mean line of sight
reddening for about a hundred main-sequence member stars inside the
cluster is E(F435W-F555W)=1.33±0.12mag. After correcting for
foreground reddening, the total to selective extinction ratio is
RF555W=3.75±0.87 in the cluster. Within the standard deviation
associated with E(λ-F555W)/E(F435W-F555W) in each filter, the
cluster extinction curve at ultraviolet wavelengths tends to be grayer
than the average Galactic extinction laws from Cardelli et al. and
Fitzpatrick. It is closer to the extinction law derived by Calzetti et
al. for starburst galaxies, where the 0.2175µm bump is absent. This
indicates an anomalous extinction in the HD97950 cluster, which may
due to the clumpy dust distribution within the cluster, and the size
of dust grains being larger than the average Galactic ISM.
Description:
The HD97950 cluster and its immediate surroundings in the giant HII
region NGC3603 were observed with the Hubble Space Telescope (HST).
The ultraviolet (UV) data were taken with the High Resolution Channel
(HRC) of the Advanced Camera for Surveys (ACS) in 2005 (GO 10602, PI:
Jesus Maiz Apellaniz) through the F220W, F250W, F330W, and F435W
filters. The HRC is characterized by a spatial resolution of
0.03"/pixel and a field of view of 29''*25''. The optical observations
were carried out with the Wide Field and Planetary Camera 2 (WFPC2) in
two epochs: 1997 (GO 6763, PI: Laurent Drissen) and 2007 (GO 11193,
PI: Wolfgang Brandner) through the F555W, F675W, and F814W filters.
The Planetary Camera (PC) chip was centered on the cluster
(0.045"/pixel, 40''*40'') for both programs.
Pang et al. 2013 (cat. J/ApJ/764/73) reduced the two-epoch WFPC2 data
and identified more than 400 member stars on the PC chip via relative
proper motions. Of these member stars, 142 are in common between the
HRC and PC images and thus have UV and optical photometry available
(see Table1).
Among the HD97950 cluster member stars determined from relative proper
motions (Pang et al. 2013, cat. J/ApJ/764/73, Table2), there are five
main-sequence (MS) stars located in the cluster with projected
distances of r<0.7pc from the center, for which there are also
spectral types available from Table3 of Melena et al.
(2008AJ....135..878M 2008AJ....135..878M). The photometry of these five MS stars is
presented in Table2.
The individual color excesses and extinctions of the member main
sequence stars are listed in Table3.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 111 142 The ultraviolet (UV) and optical photometry of member
stars in the HD97950 cluster
table2.dat 89 5 Photometry of main sequence stars with spectral types
table3.dat 107 111 The color excesses and extinctions of member stars
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
II/114 : UV Interstellar Extinction (Savage+ 1985)
J/A+A/582/A66 : SABOCA NGC 3603 IRS 9A images (Hummel+, 2015)
J/ApJ/799/100 : Herschel FIR observations of NGC3603 (Cecco+, 2015)
J/ApJ/764/73 : HST VI photometry of HD97950 cluster members stars
(Pang+, 2013)
J/ApJ/675/1319 : Infrared photometry of NGC 3603 (Harayama+, 2008)
J/MNRAS/368/253 : Faint emission lines in M16, M20, NGC 3603
(Garcia-Rojas+, 2006)
J/AJ/127/1014 : CCD UBVRIHa photometry in NGC 3603 (Sung+, 2004)
J/MNRAS/327/23 : CCD UBVRI photometry of 7 open star clusters (Sagar+, 2001)
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 [1/142] Member star running number (internal)
5- 15 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000) (G1)
17- 27 F11.7 deg DEdeg Declination in decimal degrees (J2000)
29- 33 F5.2 mag F220W [15.3/23] HST/HRC F220W band magnitude (G2)
35- 39 F5.3 mag e_F220W [0.003/0.198] 1σ uncertainty in F220W
41- 45 F5.2 mag F250W [13.5/21.3] HST/HRC F250W band magnitude (G2)
47- 51 F5.3 mag e_F250W [0.002/0.169] 1σ uncertainty in F250W
53- 57 F5.2 mag F330W [12.6/20.1] HST/HRC F330W band magnitude (G2)
59- 63 F5.3 mag e_F330W [0.002/0.154] 1σ uncertainty in F330W
65- 69 F5.2 mag F435W [12.9/19.8] HST/HRC F435W band magnitude (G2)
71- 75 F5.3 mag e_F435W [0.002/0.077] 1σ uncertainty in F435W
77- 81 F5.2 mag F555W [11.9/18.4] HST/WFPC2 F555W band magnitude (G2)
83- 87 F5.3 mag e_F555W [0.002/0.021] 1σ uncertainty in F555W
89- 93 F5.2 mag F675W [11/17.5] HST/WFPC2 F675W band magnitude (G2)
95- 99 F5.3 mag e_F675W [0.002/0.024] 1σ uncertainty in F675W
101-105 F5.2 mag F814W [10.3/16.8] HST/WFPC2 F814W band magnitude (G2)
107-111 F5.3 mag e_F814W [0.002/0.08] 1σ uncertainty in F814W
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Name Melena et al. (2008AJ....135..878M 2008AJ....135..878M) designation
5- 15 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000) (G1)
17- 27 F11.7 deg DEdeg Declination in decimal degrees (J2000)
29- 33 F5.2 mag F220W [15.8/17.5] HST/HRC F220W band magnitude (G2)
35- 39 F5.2 mag F250W [14/15.7] HST/HRC F250W band magnitude (G2)
41- 45 F5.2 mag F330W [13.2/15] HST/HRC F330W band magnitude (G2)
47- 51 F5.2 mag F435W [13.6/15.4] HST/HRC F435W band magnitude (G2)
53- 57 F5.2 mag F555W [12.6/14.5] HST/WFPC2 F555W band magnitude (G2)
59- 63 F5.2 mag F675W [11.7/13.5] HST/WFPC2 F675W band magnitude (G2)
65- 69 F5.2 mag F814W [11/12.9] HST/WFPC2 F814W band magnitude (G2)
71- 75 A5 --- SpT Spectral Type
77- 82 F6.3 mag (U-B)0 [-1.221/-1.183] Empirical ZAMS (U-B) color
index (1)
84- 89 F6.3 mag (B-V)0 [-0.321/-0.32] Empirical ZAMS (B-V) color
index (1)
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Note (1): The colors (U-B)0 and (B-V)0 are taken from the empirical Zero-Age
Main Sequence (ZAMS) of Sparke & Gallagher (2007gitu.book.....S 2007gitu.book.....S).
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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 --- Name [1/111] Member star running number (internal)
5- 15 F11.7 deg RAdeg Right Ascension in decimal degrees (J2000) (G1)
17- 27 F11.7 deg DEdeg Declination in decimal degrees (J2000)
29- 32 F4.2 mag E220-435 [4.3/5.5] Individual star color excess,
E(F220W-F435W)
34- 38 F5.3 mag E250-435 [2.4/3.4] Individual star color excess,
E(F250W-F435W)
40- 43 F4.2 mag E330-435 [1.1/2] Individual star color excess,
E(F330W-F435W)
45- 49 F5.3 mag E435-555 [1.1/2] Individual star color excess,
E(F435W-F555W)
51- 54 F4.2 mag E555-675 [1/1.3] Individual star color excess,
E(F555W-F675W)
56- 60 F5.3 mag E555-814 [1.7/2.2] Individual star color excess,
E(F555W-F814W)
62- 66 F5.2 mag A220 [8.4/14.4] Individual star extinction (F220W)
68- 73 F6.3 mag A250 [6.2/12.2] Individual star extinction (F250W)
75- 79 F5.2 mag A330 [4.8/10.7] Individual star extinction (F330W)
81- 85 F5.3 mag A435 [3.6/9.3] Individual star extinction (F435W)
87- 90 F4.2 mag A555 [2.4/7.9] Individual star extinction (F555W)
92- 96 F5.3 mag A675 [1.3/6.8] Individual star extinction (F675W)
98-101 F4.2 mag A814 [0.5/6] Individual star extinction (F814W)
103-107 F5.3 mag R555 [2/5.7] Ratio of total to selective extinction
(F555W)
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Global Notes:
Note (G1): Positions of member stars on the PC chip of Wide Field and Planetary
Camera 2 (WFPC2) based on the 2007 data (GO 11193, PI: Wolfgang Brandner).
Note (G2): All magnitudes are Vega magnitudes in the ACS/HRC (Advanced Camera
for Surveys/High Resolution Channel) and Wide Field and Planetary Camera 2
(WFPC2) filter systems. The F555W, F675W, and F814W photometry is from 2007
data (GO 11193, PI: Wolfgang Brandner).
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 13-Jul-2016