J/ApJ/842/6 Astro-photometric catalog of the core of NGC 5139 (Bellini+, 2017)
The state-of-the-art HST astro-photometric analysis of the core
of ω Centauri.
I. The catalog.
Bellini A., Anderson J., Bedin L.R., King I.R., van der Marel R.P.,
Piotto G., Cool A.
<Astrophys. J., 842, 6-6 (2017)>
=2017ApJ...842....6B 2017ApJ...842....6B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, HST ; Proper motions
Keywords: globular clusters: individual: NGC 5139;
Hertzsprung-Russell and C-M diagrams; proper motions;
stars: Population II; techniques: photometric
Abstract:
We have constructed the most comprehensive catalog of photometry and
proper motions ever assembled for a globular cluster (GC). The core of
ωCen (NGC 5139) has been imaged over 650 times through WFC3's
UVIS and IR channels for the purpose of detector calibration. There
exist from 4 to over 60 exposures through each of 26 filters
stretching continuously from F225W in the UV to F160W in the infrared.
Furthermore, the 11yr baseline between these data and a 2002 ACS
survey has allowed us to more than double the proper-motion accuracy
and triple the number of well-measured stars compared to our previous
groundbreaking effort. This totally unprecedented complete spectral
coverage of over 470000 stars within the cluster's core, from the tip
of the red giant branch down to the white dwarfs, provides the best
astro-photometric observational database yet to understand the
multiple-population phenomenon in any GC. In this first paper of the
series, we describe in detail the data-reduction processes and deliver
the astro-photometric catalog to the astronomical community.
Description:
The core of ω Cen (NGC 5139) has been observed through many of
the WFC3 filters since 2009 for calibration purposes, and new
observations continue to be scheduled. Table 1 summarizes the massive
archive of data, organized in a camera/filter fashion. We downloaded
from the archive a total of 655 exposures (∼205Ks) taken through 26
HST different bands: 18 for WFC3/UVIS (385 exposures) and 8 for
WFC3/IR (270 exposures); spanning 2009 July to 2013 March. This data
set can be accessed at MAST via this link:
http://archive.stsci.edu/doi/resolve/resolve.html?doi=10.17909/T9WG6S
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 131 26 List of HST WFC3 observations of the core
of NGC5139
table3.dat 214 478477 *Astrometric data
method1.dat 83 12440402 *The Method-one photometric file
method2.dat 59 12440402 *The Method-two photometric file
method3.dat 59 12440402 *The Method-three photometric file
table6.dat 107 550000 Artificial-star-tests file
files/* . 80 Original files sent by the author
--------------------------------------------------------------------------------
Note on table3.dat: Proper motion information from Bellini+, 2014, J/ApJ/797/115
Note on method1.dat:
KS2 (FORTRAN software package kitchen_sync2, J. Anderson 2017, in
preparation; see also Section 3 of Sabbi+ 2016,J/ApJS/222/11 for an
in-depth description of the software) has three approaches for
measuring stars.
The first approach can only be applied when a star generates a
distinct peak within its local 5x5pixel, neighbor-subtracted raster.
When that happens, we can measure a position and flux for the star
using the PSF appropriate for that location in that exposure.
See section 3.3 for further explanations.
Note on method2.dat:
Method two takes the position determined in the finding stage and uses
that position and the PSF to determine a best-fit flux from the inner
3x3 pixels.
See section 3.3 for further explanations.
Note on method3.dat:
Method three is similar to method two, but it uses the brightest four
pixels and weights them by the expected values of the PSF in those
pixels, which is appropriate when the source is much fainter than the
background noise.
See section 3.3 for further explanations.
--------------------------------------------------------------------------------
Description of file:
In the FTP section the directory "files" contains all the original
files sent by the author:
IDXYRD_PM.dat is equivalent to Table 3,
AS_IO.dat is the AS-test file equivalent to Table 6.
Then for each filter, the author provides a distinct file for each
photometric method containing magnitudes and quality parameters (e.g.,
F606W.m1.dat, F606W.m2.dat, and F606W.m3.dat for methods one, two, and
three, respectively). Each of these files starts with a header
containing a column-by-column description of the contained data,
followed by the same number of ordered data lines, one for each star.
See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+AS/115/297 : BVRI photometry of Central Field of ω Cen (Lynga+, 1996)
J/ApJ/654/915 : Deep FORS1 BR photometry of omega Cen (Sollima+, 2007)
J/ApJ/663/296 : omega Cen (NGC5139) subgiants UBVRIc phot. (Villanova+, 2007)
J/A+A/493/959 : UBV(RI)cHalpha photometry in omega Cen (Bellini+, 2009)
J/ApJ/710/1032 : Proper motions in ω Cen (Anderson+, 2010)
J/AJ/140/631 : HST WFC3/UVIS photometry of omega Cen core (Bellini+, 2010)
J/ApJ/751/6 : Radial velocities in ω Cen (Da Costa, 2012)
J/ApJ/797/115 : HSTPROMO I. Observations and NGC7078 results (Bellini+, 2014)
J/ApJ/844/164 : HST astro-photometric data for NGC5139. III. (Bellini+, 2017)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Inst Instrument (WFC3/UVIS or WFC3/IR)
11- 16 A6 --- Filt Filter name (1)
18- 39 A22 s Exp Exposures
41- 45 I5 s Time [908/27600] Total time
47- 51 I5 --- PID1 Program ID
53- 57 I5 --- PID2 ? Second program ID if any
59- 63 I5 --- PID3 ? Third program ID if any
65- 69 I5 --- PID4 ? Fourth program ID if any
71- 75 I5 --- PID5 ? Fifth program ID if any
77- 81 I5 --- PID6 ? Sixth program ID if any
83- 87 I5 --- PID7 ? Seventh program ID if any
89- 93 I5 --- PID8 ? Eighth program ID if any
95-121 A27 --- Comm Description
123-131 A9 --- Date Epoch
--------------------------------------------------------------------------------
Note (1): Photometric-calibration Zero Points (table 2):
------------------------------------------------------
Filter Delmag ZP (VEGA)
(mag) (mag)
------------------------------------------------------
WFC3/UVIS
------------------------------------------------------
F225W +7.0889 (+7.3856 -0.2967) +22.3808
F275W +7.0240 (+7.2577 -0.2337) +22.6322
F336W +6.1648 (+6.3602 -0.1954) +23.4836
F350LP +6.1925 (+6.3602 -0.1677) +26.7874
F390M +6.1867 (+6.3602 -0.1735) +23.5377
F390W +6.2007 (+6.3602 -0.1595) +25.1413
F438W +6.1961 (+6.3602 -0.1641) +24.9738
F467M +6.4827 (+6.6330 -0.1503) +23.8362
F555W +3.8302 (+4.0051 -0.1749) +25.8160
F606W +3.8517 (+4.0051 -0.1534) +25.9866
F621M +6.9822 (+7.1251 -0.1429) +24.4539
F656N +6.6090 (+6.7474 -0.1384) +19.8215
F658N +6.2200 (+6.3602 -0.1402) +20.6795
F673N +6.2313 (+6.3602 -0.1289) +22.3297
F775W +6.4621 (+6.6330 -0.1709) +24.4747
F814W +3.8445 (+4.0051 -0.1616) +24.6803
F850LP +4.2503 (+4.4454 -0.1951) +23.3130
F953N +7.1632 (+7.3235 -0.1603) +19.7549
------------------------------------------------------
WFC3/IR
------------------------------------------------------
F098M -0.0736 +25.1057
F105W -0.0335 +25.6236
F110W -0.0743 +26.0628
F125W -0.0844 +25.3293
F139M -0.0633 +23.4006
F140W -0.1262 +25.3761
F153M -0.0636 +23.2098
F160W -0.0756 +24.6949
------------------------------------------------------
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID [1/478477] Identification number
8- 14 F7.2 pix Xpix X-position on the master frame
16- 22 F7.2 pix Ypix Y-position on the master frame
24- 25 I2 h RAh [13] Hour of Right Ascension (J2000)
27- 28 I2 min RAm [26/27] Minute of Right Ascension (J2000)
30- 35 F6.3 s RAs Second of Right Ascension (J2000)
37 A1 --- DE- [-] Sign of the Declination (J2000)
38- 39 I2 deg DEd [47] Degree of Declination (J2000)
41- 42 I2 arcmin DEm [25/31] Arcminute of Declination (J2000)
44- 48 F5.2 arcsec DEs Arcsecond of Declination (J2000)
50- 58 F9.4 mas/yr pmRA [-18/12]?=-999.999 Proper motion along RA
times cos(DE)
60- 68 F9.4 mas/yr pmDE [-14/16]?=-999.999 Proper motion along DE
70- 78 F9.4 mas/yr e_pmRA [0.003/4]?=-999.999 1σ uncertainty
in pmRA computed using actual residuals
80- 88 F9.4 mas/yr e_pmDE [0.005/4]?=-999.999 1σ uncertainty
in pmDE computed using actual residuals
90- 98 F9.4 mas/yr epmRA [0.004/4]?=-999.999 The 1σ uncertainty
in pmRA computed using expected errors
100-108 F9.4 mas/yr epmDE [0.004/4]?=-999.999 The 1σ uncertainty
in pmDE computed using expected errors
110-118 F9.4 --- QpmRA [0.1/67]?=-999.999 Reduced χ2 of fit
to pmRA
120-128 F9.4 --- QpmDE [0.1/87]?=-999.999 Reduced χ2 of fit
to pmDE
130-138 F9.4 pix sigmaX [0.0005/0.4]?=-999.999 The 1σ uncertainty
in intercept of PM fit for RA component
computed using actual residuals
140-148 F9.4 pix sigmaY [0.0005/0.4]?=-999.999 The 1σ uncertainty
in intercept of PM fit for DE component
computed using actual residuals
150-159 F10.5 yr Time [0.7/11]?=-999.999 Time baseline; Julian years
161-169 F9.4 pix errX [0.0006/0.3]?=-999.999 The 1σ uncertainty
in intercept of PM fit for RA component
using expected errors
171-179 F9.4 pix errY [0.0005/0.4]?=-999.999 The 1σ uncertainty
in intercept of PM fit for DE component
using expected errors
181-184 I4 --- Uref [0/1]?=-999 Reference star flag; 1=Yes, 0=No
186-189 I4 --- Nfound [7/281]?=-999 Total number of data points
available for PM fits
191-194 I4 --- Nused [5/281]?=-999 Final number of data points used
for PM fits
196-204 F9.4 mas/yr DelpmRA [-0.5/0.5]?=-999.999 Difference in pmRA (1)
206-214 F9.4 mas/yr DelpmDE [-0.5/0.6]?=-999.999 Difference in pmDE (1)
--------------------------------------------------------------------------------
Note (1): Between locally-corrected and amplifier-based PMs.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: method*.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Filt Filter identifier; see Table 1
8- 13 I6 --- ID [1/478477] Identification number as in Table 3;
column added by CDS
16- 23 F8.4 mag mag [9.1/32.6]?=-99.999 Apparent Vega magnitude
in Filt (1)
25- 34 F10.4 mag e_mag [0/96973]?=-99.999 RMS uncertainty in mag (1)
36- 37 I2 --- Nf [0/71] Number of exposures a star found in
40- 41 I2 --- Ng [0/71] Number of good measurements
44- 48 F5.3 --- QFIT [0/1]? Quality-of-fit parameter
49 A1 --- f_QFIT [*] *: QFIT not available (only one measurement
in method3)
51- 59 F9.2 --- fL [-18.3/20124] Fraction of light in aperture
from neighbors
65- 69 F5.1 ct sky [0/999.9]? Local sky-background value
(only for Method One)
75- 79 F5.1 ct RMS [0/999.9]? RMS of sky
(only for Method One)
83 I1 --- Sat [0/1]? Saturation flag, UVIS filters only:
1=saturated (only for Method One)
--------------------------------------------------------------------------------
Note (1): If a star is found in only one exposure, it is not
possible to compute its photometric rms, and a flag value of -99.999
is used. If a star is not measured in one particular filter, both its
magnitude and rms will be flagged at -99.999.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.4 pix XInpix Input X pixel position
11- 19 F9.4 pix YInpix Input Y pixel position
21- 28 F8.4 mag F606WInmag [-14/-3] Input F606W instrumental magnitude
30- 37 F8.4 mag F438WInmag [-14/-0.08] Input F438W instrumental magnitude
39- 45 F7.2 pix XRecpix Recovered X pixel position
47- 53 F7.2 pix YRecpix Recovered Y pixel position
55- 62 F8.4 mag F606WM1mag [-90.1/-0] Recovered method 1 F606W magnitude
64- 71 F8.4 mag F438WM1mag [-90.1/-0] Recovered method 1 F438W magnitude
73- 80 F8.4 mag F606WM2mag [-90.1/-0] Recovered method 2 F606W magnitude
82- 89 F8.4 mag F438WM2mag [-90.1/-0] Recovered method 2 F438W magnitude
91- 98 F8.4 mag F606WM3mag [-90.1/-0] Recovered method 3 F606W magnitude
100-107 F8.4 mag F438WM3mag [-90.1/-0] Recovered method 3 F438W magnitude
--------------------------------------------------------------------------------
History:
From electronic version of the journal
16-May-2018: Tables 1, 3, 4, 5 and 6 insert into VizieR
16-Nov-2021: Table 5 was incomplete --
AAS Tables 4 and 5 removed and method1, method2 and method3 tables
added (from the files sent by the author) + files per filter (sent by
the author) added on the FTP section
Acknowledgements:
Andrea Bellini
References:
Bellini et al. Paper I. 2017ApJ...842....6B 2017ApJ...842....6B This catalog
Bellini et al. Paper II. 2017ApJ...842....7B 2017ApJ...842....7B
Bellini et al. Paper III. 2017ApJ...844..164B 2017ApJ...844..164B Cat. J/ApJ/844/164
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Jan-2018