OPTICAL PHOTOMETRIC GTC/OSIRIS OBSERVATIONS OF THE YOUNG MASSIVE ASSOCIATION CYGNUS OB2

Journal Article · Mon Oct 15 00:00:00 EDT 2012 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/202/2/19· OSTI ID:22089831

Guarcello, M. G.; Wright, N. J.; Drake, J. J.; Aldcroft, T.; Kashyap, V. L. ^[1]; Garcia-Alvarez, D. ^[2]; Drew, J. E. ^[3]

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1. Smithsonian Astrophysical Observatory, MS-67, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)
3. CAR/STRI, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom)

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 10.4 m Gran Telescopio CANARIAS telescope, which is the deepest optical catalog of Cyg OB2 to date. The catalog consists of 64,157 sources down to M = 0.15 M{sub Sun} 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 2.64{sup m} < A{sub V} < 5.57{sup m} range. We derive an extinction map of the region, finding a median value of A{sub V} = 4.33{sup m} 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 {approx}850 {+-} 25 pc from the Sun.

• OSTI ID: 22089831
• Journal Information: Astrophysical Journal, Supplement Series, Vol. 202, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTRONOMY
ASTROPHYSICS
CATALOGS
COLOR
COSMIC X-RAY SOURCES
GALAXIES
GRAVITATIONAL COLLAPSE
PHOTOMETRY
STAR EVOLUTION
SUN
TELESCOPES