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The Palomar Transient Factory Photometric Calibration

Ofek, E. O. and Laher, R. and Law, N. and Surace, J. and Levitan, D. and Sesar, B. and Horesh, A. and Poznanski, D. and van Eyken, J. C. and Kulkarni, S. R. and Nugent, P. and Zolkower, J. and Walters, R. and Sullivan, M. and Agüeros, M. and Bildsten, L. and Bloom, J. S. and Cenko, S. B. and Gal-Yam, A. and Grillmair, C. and Helou, G. and Kasliwal, M. M. and Quimby, R. (2012) The Palomar Transient Factory Photometric Calibration. Publications of the Astronomical Society of the Pacific, 124 (911). pp. 62-73. ISSN 0004-6280.

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The Palomar Transient Factory (PTF) provides multiple epoch imaging for a large fraction of the celestial sphere. Here, we describe the photometric calibration of the PTF data products that allows the PTF magnitudes to be related to other magnitude systems. The calibration process utilizes Sloan Digital Sky Survey (SDSS) r ∼ 16 mag point-source objects as photometric standards. During photometric conditions, this allows us to solve for the extinction coefficients and color terms and to estimate the camera illumination correction. This also enables the calibration of fields that are outside the SDSS footprint. We test the precision and repeatability of the PTF photometric calibration. Given that PTF is observing in a single filter each night, we define a PTF calibrated magnitude system for the R band and g band. We show that, in this system, ≈59% (47%) of the photometrically calibrated PTF R-band (g-band) data achieve a photometric precision of 0.02–0.04 mag and have color terms and extinction coefficients that are close to their average values. Given the objects’ color, the PTF magnitude system can be converted to other systems. Moreover, a night-by-night comparison of the calibrated magnitudes of individual stars observed on multiple nights shows that they are consistent to a level of ≈0.02 mag. Most of the data that were taken under nonphotometric conditions can be calibrated relative to other epochs of the same sky footprint obtained during photometric conditions. We provide a concise guide describing how to use the PTF photometric-calibration data products, as well as the transformations between the PTF magnitude system and the SDSS and Johnson-Cousins systems.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper DOIArticle
Ofek, E. O.0000-0002-6786-8774
Laher, R.0000-0003-2451-5482
Law, N.0000-0001-9380-6457
Surace, J.0000-0001-7291-0087
Sesar, B.0000-0002-0834-3978
Horesh, A.0000-0002-5936-1156
van Eyken, J. C.0000-0003-2192-5371
Kulkarni, S. R.0000-0001-5390-8563
Nugent, P.0000-0002-3389-0586
Walters, R.0000-0002-1835-6078
Sullivan, M.0000-0001-9053-4820
Agüeros, M.0000-0001-7077-3664
Bloom, J. S.0000-0002-7777-216X
Cenko, S. B.0000-0003-1673-970X
Gal-Yam, A.0000-0002-3653-5598
Grillmair, C.0000-0003-4072-169X
Helou, G.0000-0003-3367-3415
Kasliwal, M. M.0000-0002-5619-4938
Quimby, R.0000-0001-9171-5236
Additional Information:© 2012 The Astronomical Society of the Pacific. Received 2011 August 21; accepted 2011 December 5; published 2012 January 30. We thank Andrew Pickles and an anonymous referee for useful comments on the article. This article is based on observations obtained with the Samuel Oschin Telescope as part of the Palomar Transient Factory project, a scientific collaboration between the California Institute of Technology, Columbia University, Las Cumbres Observatory, the Lawrence Berkeley National Laboratory, the National Energy Research Scientific Computing Center, the University of Oxford, and theWeizmann Institute of Science. E. O. O. is supported by an Einstein fellowship and NASA grants. S. R. K. and his group are partially supported by the NSF grant AST-0507734. S. B. C. acknowledges generous financial assistance from Gary and Cynthia Bengier, the Richard and Rhoda Goldman Fund, NASA/Swift grants NNX10AI21G and GO-7100028, the TABASGO Foundation, and NSF grant AST-0908886.
Group:Palomar Transient Factory, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA Einstein FellowshipUNSPECIFIED
Gary and Cynthia BengierUNSPECIFIED
Richard and Rhoda Goldman FundUNSPECIFIED
Issue or Number:911
Record Number:CaltechAUTHORS:20131210-082130611
Persistent URL:
Official Citation:The Palomar Transient Factory Photometric Calibration E. O. Ofek, R. Laher, N. Law, J. Surace, D. Levitan, B. Sesar, A. Horesh, D. Poznanski, J. C. van Eyken, S. R. Kulkarni, P. Nugent, J. Zolkower, R. Walters, M. Sullivan, M. Agüeros, L. Bildsten, J. Bloom, S. B. Cenko, A. Gal-Yam, C. Grillmair, G. Helou, M. M. Kasliwal and R. Quimby Publications of the Astronomical Society of the Pacific , Vol. 124, No. 911 (January 2012), pp. 62-73 Published by: The University of Chicago Press on behalf of the Astronomical Society of the Pacific Article DOI: 10.1086/664065 Article Stable URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42915
Deposited By: Tony Diaz
Deposited On:10 Dec 2013 19:54
Last Modified:20 Nov 2019 20:38

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