Aperture Photometry Tool Versus SExtractor for Noncrowded Fields

Laher, Russ R. and Rebull, Luisa M. and Gorjian, Varoujan and Masci, Frank J. and Fowler, John W. and Grillmair, Carl and Surace, Jason and Mattingly, Sean and Jackson, Ed and Hacopeans, Eugean and Hamam, Nouhad and Groom, Steve and Teplitz, Harry and Mi, Wei and Helou, George and van Eyken, Julian C. and Law, Nicholas M. and Dekany, Richard G. and Rahmer, Gustavo and Hale, David and Smith, Roger and Quimby, Robert M. and Ofek, Eran O. and Kasliwal, Mansi M. and Zolkower, Jeff and Velur, Viswa and Walters, Richard and Henning, John and Bui, Khahn and McKenna, Dan and Kulkarni, Shrinivas R. (2012) Aperture Photometry Tool Versus SExtractor for Noncrowded Fields. Publications of the Astronomical Society of the Pacific, 124. pp. 764-781. ISSN 0004-6280, 1538-3873

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Abstract

Outputs from new software program Aperture Photometry Tool (APT) are compared with similar outputs from SExtractor for sources extracted from R-band optical images acquired by the Palomar Transient Factory (PTF), infrared mosaics constructed from Spitzer Space Telescope images, and a processed visible/near-infrared image from the Hubble Legacy Archive (HLA). Two large samples from the PTF images are studied, each containing around 3 × 103 sources from noncrowded fields. The median values of source-intensity relative percentage differences between the two software programs, computed separately for two PTF samples, are þ0:13% and þ0:17%, with corresponding statistical dispersions of 1.43% and 1.84%, respectively. For the Spitzer mosaics, a similar large sample of extracted sources for each of channels 1–4 of Spitzer’s Infrared Array Camera (IRAC) are analyzed with two different sky annulus sizes, and we find that the median and modal values of source-intensity relative percentage differences between the two software programs are between �0:5% and þ2:0%, and the corresponding statistical dispersions range from 1.4 to 6.7%, depending on the Spitzer IRAC channel and sky annulus. The results for the HLA image are mixed, as might be expected for a moderately crowded field. The comparisons for the three different kinds of images show that there is generally excellent agreement between APT and SExtractor. Differences in source-intensity uncertainty estimates for the PTF images amount to less than 3% for the PTF sources, and these are potentially caused by SExtractor’s omission of the sky background uncertainty term in the formula for source-intensity uncertainty, as well as differing methods of sky background estimation.

Item Type: Article
Subjects: RTSRE Related Research
Depositing User: Dr Michael Fitzgerald
Date Deposited: 17 May 2017 08:37
Last Modified: 17 May 2017 08:37
URI: http://istardb.org/id/eprint/877

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