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Title: The Subaru/ XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey

Abstract

We present our survey for optically faint variable objects using multiepoch (8-10 epochs over 2-4 years) i'-band imaging data obtained with Subaru Suprime-Cam over 0.918 deg 2 in the Subaru/ XMM-Newton Deep Field (SXDF). We found 1040 optically variable objects by image subtraction for all the combinations of images at different epochs. This is the first statistical sample of variable objects at depths achieved with 8-10 m class telescopes or the Hubble Space Telescope. The detection limit for variable components is i' vari∼ 25.5 mag. These variable objects were classified into variable stars, supernovae (SNe), and active galactic nuclei (AGNs), based on the optical morphologies, magnitudes, colors, and optical-mid-infrared colors of the host objects, spatial offsets of variable components from the host objects, and light curves. Detection completeness was examined by simulating light curves for periodic and irregular variability. We detected optical variability for 36% ± 2% (51% ± 3% for a bright sample with i' < 24.4 mag) of X-ray sources in the field. Number densities of variable objects as functions of time intervals Δ t and variable component magnitudes i' vari are obtained. Number densities of variable stars, SNe, and AGNs are 120, 489, and 579 objects degmore » -2, respectively. Bimodal distributions of variable stars in the color-magnitude diagrams indicate that the variable star sample consists of bright (V ∼ 22 mag) blue variable stars of the halo population and faint (V ∼ 23.5 mag) red variable stars of the disk population. Lastly, there are a few candidates of RR Lyrae providing a possible number density of ∼10 -2 kpc -3 at a distance of >150 kpc from the Galactic center.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [4];  [6];  [6];  [6];  [7];  [7];  [8];  [9];  [10];  [11];  [12];  [13];  [13];  [13];  [14] more »;  [15];  [16] « less
  1. National Astronomical Observatory, Tokyo (Japan). Optical and Infrared Astronomy Division; Univ. of Tokyo (Japan). Inst. of Astronomy, Graduate School of Science
  2. Univ. of Tokyo (Japan). Inst. of Astronomy, Graduate School of Science
  3. Univ. of Tokyo (Japan). Inst. for Cosmic Ray Research
  4. National Astronomical Observatory of Japan, Hilo, HI (United States). Subaru Telescope
  5. National Astronomical Observatory, Tokyo (Japan). Optical and Infrared Astronomy Division; National Astronomical Observatory of Japan, Hilo, HI (United States). Subaru Telescope
  6. Kyoto Univ. (Japan). Dept. of Astronomy
  7. National Astronomical Observatory, Tokyo (Japan). Optical and Infrared Astronomy Division
  8. Tohoku Univ., Sendai (Japan). Astronomical Inst., Graduate School of Science
  9. Space Telescope Science Inst., Baltimore, MD (United States)
  10. Univ. of Leicester, Leicester (United Kingdom). Dept. of Physics and Astronomy
  11. Rochester Inst. of Technology, Rochester, NY (United States). Dept. of Physics
  12. European Southern Observatory, Santiago (Chile)
  13. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  14. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Texas A & M Univ., College Station, TX (United States). Dept. of Physics
  15. Univ. of Oxford (United Kingdom). Dept. of Astrophysics
  16. Vanderbilt Univ., Nashville, TN (United States). Dept. of Physics and Astronomy
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1511305
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 676; Journal Issue: 1; Journal ID: ISSN 0004-637X
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: active; stars: variables: other; supernovae: general; surveys

Citation Formats

Morokuma, Tomoki, Doi, Mamoru, Yasuda, Naoki, Akiyama, Masayuki, Sekiguchi, Kazuhiro, Furusawa, Hisanori, Ueda, Yoshihiro, Totani, Tomonori, Oda, Takeshi, Nagao, Tohru, Kashikawa, Nobunari, Murayama, Takashi, Ouchi, Masami, Watson, Mike G., Richmond, Michael W., Lidman, Christopher, Perlmutter, Saul, Spadafora, Anthony L., Aldering, Greg, Wang, Lifan, Hook, Isobel M., and Knop, Rob A. The Subaru/XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey. United States: N. p., 2008. Web. doi:10.1086/527467.
Morokuma, Tomoki, Doi, Mamoru, Yasuda, Naoki, Akiyama, Masayuki, Sekiguchi, Kazuhiro, Furusawa, Hisanori, Ueda, Yoshihiro, Totani, Tomonori, Oda, Takeshi, Nagao, Tohru, Kashikawa, Nobunari, Murayama, Takashi, Ouchi, Masami, Watson, Mike G., Richmond, Michael W., Lidman, Christopher, Perlmutter, Saul, Spadafora, Anthony L., Aldering, Greg, Wang, Lifan, Hook, Isobel M., & Knop, Rob A. The Subaru/XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey. United States. doi:10.1086/527467.
Morokuma, Tomoki, Doi, Mamoru, Yasuda, Naoki, Akiyama, Masayuki, Sekiguchi, Kazuhiro, Furusawa, Hisanori, Ueda, Yoshihiro, Totani, Tomonori, Oda, Takeshi, Nagao, Tohru, Kashikawa, Nobunari, Murayama, Takashi, Ouchi, Masami, Watson, Mike G., Richmond, Michael W., Lidman, Christopher, Perlmutter, Saul, Spadafora, Anthony L., Aldering, Greg, Wang, Lifan, Hook, Isobel M., and Knop, Rob A. Thu . "The Subaru/XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey". United States. doi:10.1086/527467. https://www.osti.gov/servlets/purl/1511305.
@article{osti_1511305,
title = {The Subaru/XMM-Newton Deep Survey (SXDS). V. Optically Faint Variable Object Survey},
author = {Morokuma, Tomoki and Doi, Mamoru and Yasuda, Naoki and Akiyama, Masayuki and Sekiguchi, Kazuhiro and Furusawa, Hisanori and Ueda, Yoshihiro and Totani, Tomonori and Oda, Takeshi and Nagao, Tohru and Kashikawa, Nobunari and Murayama, Takashi and Ouchi, Masami and Watson, Mike G. and Richmond, Michael W. and Lidman, Christopher and Perlmutter, Saul and Spadafora, Anthony L. and Aldering, Greg and Wang, Lifan and Hook, Isobel M. and Knop, Rob A.},
abstractNote = {We present our survey for optically faint variable objects using multiepoch (8-10 epochs over 2-4 years) i'-band imaging data obtained with Subaru Suprime-Cam over 0.918 deg2 in the Subaru/XMM-Newton Deep Field (SXDF). We found 1040 optically variable objects by image subtraction for all the combinations of images at different epochs. This is the first statistical sample of variable objects at depths achieved with 8-10 m class telescopes or the Hubble Space Telescope. The detection limit for variable components is i'vari∼ 25.5 mag. These variable objects were classified into variable stars, supernovae (SNe), and active galactic nuclei (AGNs), based on the optical morphologies, magnitudes, colors, and optical-mid-infrared colors of the host objects, spatial offsets of variable components from the host objects, and light curves. Detection completeness was examined by simulating light curves for periodic and irregular variability. We detected optical variability for 36% ± 2% (51% ± 3% for a bright sample with i' < 24.4 mag) of X-ray sources in the field. Number densities of variable objects as functions of time intervals Δt and variable component magnitudes i'vari are obtained. Number densities of variable stars, SNe, and AGNs are 120, 489, and 579 objects deg-2, respectively. Bimodal distributions of variable stars in the color-magnitude diagrams indicate that the variable star sample consists of bright (V ∼ 22 mag) blue variable stars of the halo population and faint (V ∼ 23.5 mag) red variable stars of the disk population. Lastly, there are a few candidates of RR Lyrae providing a possible number density of ∼10-2 kpc-3 at a distance of >150 kpc from the Galactic center.},
doi = {10.1086/527467},
journal = {Astrophysical Journal},
number = 1,
volume = 676,
place = {United States},
year = {2008},
month = {3}
}

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