J/ApJS/202/19 riz photometry in Cyg OB2 (Guarcello+, 2012)
Optical photometric GTC/OSIRIS observations of the young massive association
Cygnus OB2.
Guarcello M.G., Wright N.J., Drake J.J., Garcia-Alvarez D., Drew J.E.,
Aldcroft T., Kashyap V.L.
<Astrophys. J. Suppl. Ser., 202, 19 (2012)>
=2012ApJS..202...19G 2012ApJS..202...19G
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ;
Photometry, ugriz
Keywords: catalogs - stars: formation - stars: pre-main sequence
Abstract:
In order to fully understand the gravitational collapse of molecular
clouds, the star formation process, and the evolution of circumstellar
disks, these phenomena must be studied in different Galactic
environments with a range of stellar contents and positions in the
Galaxy. The young massive association Cygnus OB2, in the Cygnus-X
region, is a unique target to study how star formation and the
evolution of circumstellar disks proceed in the presence of a large
number of massive stars. We present a catalog obtained with recent
optical observations in the r, i, z filters with OSIRIS, mounted on
the 10.4m Gran Telescopio CANARIAS telescope, which is the deepest
optical catalog of CygOB2 to date. The catalog consists of 64,157
sources down to M=0.15M☉ at the adopted distance and age of Cyg
OB2. A total of 38,300 sources have good photometry in all three
bands. We combined the optical catalog with existing X-ray data of
this region, in order to define the cluster locus in the optical
diagrams. The cluster locus in the r-i versus i-z diagram is
compatible with an extinction of the optically selected cluster
members in the 2.64m<AV<5.57m range. We derive an extinction map of
the region, finding a median value of AV=4.33m in the center of the
association, decreasing toward the northwest. In the color-magnitude
diagrams, the shape of the distribution of main-sequence stars is
compatible with the presence of an obscuring cloud in the foreground
∼850±25pc from the Sun.
Description:
The observations were performed in the r', i', and z' filters with
OSIRIS, mounted on the 10.4m Gran Telescopio CANARIAS (GTC) of the
Spanish Observatorio del Roque de los Muchachos in La Palma, between
2009-09-11 and 2009-09-22. The scale on the detector is 0.127arcsec/pix
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
cygob2.dat 84 64157 Final OSIRIS catalog of Cyg OB2 (table3 of paper)
--------------------------------------------------------------------------------
See also:
J/AJ/107/1433 : Cygnus OB2 polarimetry (Kobulnicky+, 1994)
J/A+AS/111/407 : VI Cygni red + reddened stars (Parthasarathy+, 1995)
J/MNRAS/298/753 : Variables in Cygnus OB2 (Pigulski+ 1998)
J/ApJS/149/123 : WSRT survey of Cygnus OB2 (Setia Gunawan+, 2003)
J/ApJ/643/238 : Chandra/2MASS sources in Cygnus OB2 (Butt+, 2006)
J/A+A/464/211 : Chandra and near-IR obs. of Cyg OB2 (Albacete Colombo+, 2007)
J/A+A/472/557 : Cygnus OB2 region 610MHz sources (Marti+, 2007)
J/A+A/474/495 : Cygnus OB2 young stars X-ray flares (Albacete Colombo+, 2008)
J/A+A/486/453 : NIR photometry of early-type stars in CygOB2 (Comeron+, 2008)
J/ApJS/184/84 : X-ray sources in Cyg OB2 region (Wright+, 2009)
J/ApJS/194/27 : Variable stars in Cygnus OB2 (Henderson+, 2011)
J/A+A/543/A101 : OB stars in Cygnus OB2 association (Comeron+, 2012)
J/ApJ/713/871 : Sources in Cyg-OB2 from X-ray (Wright+, 2012)
Byte-by-byte Description of file: cygob2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- ID [1/64157] Sequential source ID
7- 17 F11.7 deg RAdeg Right ascension (J2000)
19- 29 F11.7 deg DEdeg Declination (J2000)
31- 37 F7.4 mag rmag ?=0 Magnitude in r band in the AB system
39- 43 F5.3 mag e_rmag ?=0 Error associated with r magnitude
45- 51 F7.4 mag imag ?=0 Magnitude in i band in the AB system
53- 57 F5.3 mag e_imag ?=0 Associated with i magnitude
59- 65 F7.4 mag zmag ?=0 Magnitude in z band in the AB system
67- 72 F6.3 mag e_zmag ?=0 Error associated with z magnitude
74- 78 F5.2 --- chi χ2 from the PSF fitting (1)
80- 84 F5.2 --- Sharp Sharp parameter describing the stellar profile (1)
--------------------------------------------------------------------------------
Note (1): DAOPHOT sharpness parameter, see Stetson 1987PASP...99..191S 1987PASP...99..191S
(zero for stellar fit). The sharp and χ2 values are set to zero
for sources detected only in one band (z' usually).
--------------------------------------------------------------------------------
Acknowledgements:
Guarcello Mario Giuseppe, mguarcel(at)head.cfa.harvard.edu
(End) Guarcello Mario Giuseppe [CfA, USA], Patricia Vannier [CDS] 15-Nov-2012