J/A+A/544/A155 HST photometry of M31 globular clusters (Federici+, 2012)
The horizontal branch luminosity vs. metallicity in M31 globular clusters.
Federici L., Cacciari C., Bellazzini M., Fusi Pecci F., Galleti S.,
Perina S.
<Astron. Astrophys., 544, A155-155 (2012)>
=2012A&A...544A.155F 2012A&A...544A.155F
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Photometry, HST
Keywords: galaxies: individual: M 31 - galaxies: star clusters: general -
catalogs - Local Group - techniques: photometric
Abstract:
We have derived a new calibration of the MV(HB)-[Fe/H] relation by
exploiting the large photometric database of old GCs in M31 in the HST
archive. We collected BVI data for 48 old GCs in M31 and analysed them
by applying the same methods and procedures to all objects. We
obtained a set of homogeneous colour-magnitude diagrams (CMDs) that
were best-fitted with the fiducial CMD ridge lines of selected Milky
Way template GCs. Reddening, metallicity, horizontal branch (HB)
luminosity and distance were determined self-consistently for each
cluster. There are three main results of this study: i) the relation
MV(HB)=0.25(±0.02)[Fe/H]+0.89(±0.03), which is obtained from the
above parameters and is calibrated on the distances of the template
Galactic GCs; ii) the distance modulus to M31 of
(m-M)0=24.42±0.06mag, that is the first determination of the
distance to M31 based on the characteristics of its GC system, and is
calibrated on Galactic GCs, iii) the distance to the Large Magellanic
Cloud (LMC), which is estimated to be 18.54±0.07mag as a
consequence of the previous results.
Description:
Tables g58.dat, g108.dat, g105.dat, g219.dat, b468.dat, g1.dat,
g64.dat, g87.dat, g119.dat, g287.dat, g302.dat, g11.dat, g33.dat,
g76.dat, g312.dat, g319.dat, g322.dat present the photometry of the
individual stars of 17 M31 globular clusters observed with the WFPC2
on board of the HST, employing the F555W/F814W filters (Fusi Pecci et
al. 1996AJ....112.1461F 1996AJ....112.1461F (FFP96), Rich et al. 2005AJ....129.2670R 2005AJ....129.2670R (R05)).
The data reduction has been performed using ROMAFOT (Buonanno et al.
1983A&A...126..278B 1983A&A...126..278B), a multicomponent fitting package purposely
adapted to handle HST data, that provides as output the magnitudes and
the pixel positions of the detected sources. The CTE-corrected
photometric data were converted to the Johnson-Cousins V,I magnitudes
according to Holtzman et al (1995PASP..107..156H 1995PASP..107..156H).
Table g351.dat presents the photometry of the individual stars of the
M31 globular cluster B405-G351 observed with the HST/COSTAR-corrected
FOC + the F430W/F480LP filters. The data reduction has been performed
using ROMAFOT; the photometric data were converted to the
Johnson-Cousins system B,V magnitudes (see FFP96).
Tables gc1.dat, gc2.dat, gc3.dat, gc5.dat, gc6.dat, gc7.dat, gc8.dat,
gc9.dat, gc10.dat, gc4.dat, ec1.dat, ec2.dat, ec3.dat, ec4.dat present
the photometry of the individual stars of 14 M31 globular clusters
observed with the WFC/ACS on board of the HST + F435W/F606W filters
(see Galleti et al., 2006ApJ...650L.107G 2006ApJ...650L.107G; Mackey et al.,
2007ApJ...655L..85M 2007ApJ...655L..85M; Mackey et al., 2006ApJ...653L.105M 2006ApJ...653L.105M). The data
reduction has been performed using the ACS module of DOLPHOT, a point
spread function-fitting package specifically devoted to the photometry
of HST data, that provides as output the magnitudes and the pixel
positions of the detected sources, and a number of quality parameters
for a suitable sample selection. The tables present, for the ACS chip
holding the cluster, all the stars with valid measurements in both
passbands, global quality flag=1, crowding parameter <0.5, chi-square
parameter<1.5 if V>23.5,and <2.5 if V<23.5 and sharpness parameter
between -0.3 and 0.3. The x,y coordinates, the magnitudes both in the
Vegamag and in the Johnson-Cousins system, the global parameters
'chi', signal to noise, sharpness, and the ACS_WFC chip number are
listed for each of the selected stars.
BVI photometry for the clusters B008-G060, B010-G062, B023-G078,
B088-G150, B158-G213, B220-G275, B224-G279, B225-G280, B366-G291,
B407-G352,B255D-D072, B292-G010, B336-G067, B337-G068, B350-G162, and
B531 has been taken from the CDS catalogs J/A+A/507/1375 (Perina et
al., 2009) and J/A+A/531/A155 (Perina et al., 2011).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 115 32 List of studied clusters
g58.dat 44 1216 V,I Stellar Photometry of the M31 GC B006-G58 (1)
g219.dat 44 726 V,I Stellar Photometry of the M31 GC B358-G219 (1)
g108.dat 44 1228 V,I Stellar Photometry of the M31 GC B045-G108 (1)
g105.dat 44 555 V,I Stellar Photometry of the M31 GC B343-G105 (1)
b468.dat 44 335 V,I Stellar Photometry of the M31 GC B468 (1)
g1.dat 44 1987 V,I Stellar Photometry of the M31 GC G001 (1)
g351.dat 44 570 B,V Stellar Photometry of the M31 GC B405-G351 (1)
g64.dat 62 687 V,I Stellar Photometry of the M31 GC B012-G64 (1)
g87.dat 62 1123 V,I Stellar Photometry of the M31 GC B027-G87 (1)
g119.dat 62 745 V,I Stellar Photometry of the M31 GC B027-G87 (1)
g287.dat 62 756 V,I Stellar Photometry of the M31 GC B233-G287 (1)
g302.dat 62 712 V,I Stellar Photometry of the M31 GC B240-G302 (1)
g11.dat 62 805 V,I Stellar Photometry of the M31 GC B293-G11 (1)
g33.dat 62 697 V,I Stellar Photometry of the M31 GC B311-G33 (1)
g76.dat 62 958 V,I Stellar Photometry of the M31 GC B338-G76 (1)
g312.dat 62 683 V,I Stellar Photometry of the M31 GC B379-G312 (1)
g319.dat 62 420 V,I Stellar Photometry of the M31 GC B384_G319 (1)
g322.dat 62 536 V,I Stellar Photometry of the M31 GC B386-G322 (1)
gc1.dat 100 11623 V,I Stellar Photometry of the M31 GC MCGC1-B520
gc2.dat 100 14095 V,I Stellar Photometry of the M31 GC MCGC2-H4
gc3.dat 100 12447 V,I Stellar Photometry of the M31 GC MCGC3-H5
gc4.dat 100 12300 V,I Stellar Photometry of the M31 GC B514-MCGC4
gc5.dat 100 13556 V,I Stellar Photometry of the M31 GC MCGC5-H10
gc6.dat 100 79999 V,I Stellar Photometry of the M31 GC B298-G021
gc7.dat 100 22831 V,I Stellar Photometry of the M31 GC MCGC7-H14
gc8.dat 100 10234 V,I Stellar Photometry of the M31 GC MCGC8-H23
gc9.dat 100 12039 V,I Stellar Photometry of the M31 GC MCGC9-H24
gc10.dat 100 9043 V,I Stellar Photometry of the M31 GC MCGC10-H27
ec1.dat 100 34007 V,I Stellar Photometry of the M31 GC MCEC1-HEC5
ec2.dat 100 13493 V,I Stellar Photometry of the M31 GC MCEC2-HEC7
ec3.dat 100 85188 V,I Stellar Photometry of the M31 GC MCEC3-HEC4
ec4.dat 100 9297 V,I Stellar Photometry of the M31 GC MCEC4-HEC12
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Note (1): The photometry of these clusters is limited to a subsection of the
PC/WFPC2 defined by the radius r, assuming r∼300pix for the clusters B006,
B045, B343, B358, G001, and r∼80-270pix for B012, B027, B233, B240,
B293, B293, B311, B338, B379, B384, and B386 (see R05).
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See also:
J/A+A/507/1375 : HST/ACS VI data of M31 globular clusters (Perina+, 2009)
J/A+A/531/A155 : HST photometry in six M31 globular clusters (Perina+, 2011)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Cluster name
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 23 F5.2 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 35 F4.1 arcsec DEs Declination (J2000)
37- 40 I4 pix Xpos Center X position
42- 45 I4 pix Ypos Center Y position
47- 51 F5.3 arcsec/pix Scale [0.014/0.12] Scale
53- 65 A13 --- Inst Instrument: FOC, PC/WFPC2, WF3/WFPC2,
WFC/ACS chip1 or chip2
67- 74 A8 --- FileName Name of the file with photometry
76- 80 F5.2 mag Vmag [13.8/18.9] V-band magnitude
82- 87 F6.2 arcmin R [21/441] Distance from M31 nucleus
90- 93 F4.2 mag E(B-V) [0.04/0.25] Color excess
94 A1 --- u_E(B-V) Uncertainty flag (:) on E(B-V)
96-100 F5.2 [Sun] [Fe/H] [-2.15/-0.5] Metallicity
101 A1 --- u_[Fe/H] Uncertainty flag (:) on [Fe/H]
103-107 F5.2 mag V(HB) Apparent magnitude of the Horizontal Branch
108 A1 --- u_V(HB) Uncertainty flag (:) on V(HB)
110-114 F5.2 mag DM Distance modukus (nM)0_
115 A1 --- u_DM Uncertainty flag (:) on DM
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Byte-by-byte Description of file: g58.dat g10?.dat g219.dat b468.dat g1.dat
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Bytes Format Units Label Explanations
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3- 7 I5 --- ID Identification number
11- 16 F6.3 mag Vmag Johnson V magnitude
19- 24 F6.3 mag V-I Johnson V-I color index
28- 34 F7.2 pix Xpos X pixel coordinates
38- 44 F7.2 pix Ypos Y pixel coordinates
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Byte-by-byte Description of file: g351.dat
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Bytes Format Units Label Explanations
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3- 7 I5 --- ID Identification number within the cluster
11- 16 F6.3 mag Vmag Johnson V magnitude
19- 24 F6.3 mag B-V Johnson B-V color index
28- 34 F7.2 pix Xpos X pixel coordinates
38- 44 F7.2 pix Ypos Y pixel coordinates
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Byte-by-byte Description of file: g[687]?.dat g11*.dat g287.dat g3[0123]*.dat
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Bytes Format Units Label Explanations
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3- 12 F10.2 --- ID Identification number within the cluster
15- 20 F6.2 mag Vmag Johnson V magnitude
23- 28 F6.2 mag e_Vmag 1-sigma uncertainty in Vmag
31- 36 F6.2 mag Imag ?=-97.88 Johnson I magnitude
39- 44 F6.2 mag e_Imag 1-sigma uncertainty in Imag
47- 53 F7.2 pix Xpos X pixel coordinates
56- 62 F7.2 pix Ypos Y pixel coordinates
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Byte-by-byte Description of file: gc*.dat ec*.dat
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Bytes Format Units Label Explanations
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3- 8 I6 --- ID Identification number
11- 17 F7.2 pix Xpos X pixel coordinates
19- 25 F7.2 pix Ypos Y pixel coordinates
28- 33 F6.3 mag Vmag V band magnitude
35- 40 F6.3 mag Imag I band magnitude
42- 47 F6.3 mag F606W F606W band magnitude (Vegamag system)
49- 54 F6.3 mag F814W F814W band magnitude (Vegamag system)
56- 61 F6.3 mag e_F606W 1-sigma uncertainty in F606W
63- 68 F6.3 mag e_F814W 1-sigma uncertainty in F814W
71- 75 F5.3 --- Chi Value of the DOLPHOT/ACS χ statistics (1)
77- 82 F6.1 --- S/N Signal-to-Noise ratio
84- 89 F6.3 --- Sharp DOLPHOT/ACS sharpness parameter (2)
92- 96 F5.3 mag Crowd DOLPHOT/ACS crowding parameter (3)
100 I1 --- Chip ACS/WFC chip number
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Note (1): a good, clean star in an uncrowded field should have a chi-statistic
value of 1.5 or less; values up to 2.5 are reasonable. In very
crowded fields, good stars may have values up to 5.
Note (2): the DOLPHOT sharpness parameter is zero for perfect stellar fit,
negative for too broad fit (perhaps a blend, cluster or galaxy), and
positive for too sharp fit (perhaps a cosmic ray).
Note (3): the crowding parameter tells how much brighter the star would
be if nearby stars would not be fit simultaneously. The value is
zero for an isolated star.
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Acknowledgements:
Luciana Frederico, luciana.federici(at)oabo.inaf.it
(End) Patricia Vannier [CDS] 18-Jan-2013