University of Oulu

Beatriz Villarroel et al 2020 AJ 159 8.

The Vanishing and Appearing Sources during a Century of Observations project. I. USNO objects missing in modern sky surveys and follow-up observations of a “missing star”

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Author: Villarroel, Beatriz1,2; Soodla, Johan3; Comerón, Sébastien4;
Organizations: 1Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
2Instituto de Astrofisica de Canarias, Avda Via Lactea S/N, La Laguna, E-38205, Tenerife, Spain
3Department of Information Technology, Uppsala University, Uppsala, Sweden
4University of Oulu, Astronomy Research Unit, FI-90014 Oulu, Finland
5Departamento de Astrofisica, Universidad de La Laguna, E-38206 La Laguna, Tenerife, Spain
6Department of Physics and Astronomy, Texas A&M University, 4242 TAMU, College Station, TX 77843, USA
7Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, OK 73019, USA
8Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
9Statistics Netherlands, Methodology Department, Heerlen, The Netherlands
10VITO, Diepenbeek Genk, Flanders, Belgium
11Institute for Particle Physics and Astrophysics, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich, Switzerland
12Department of Astronomy, University of California Berkeley, 501 Campbell Hall#311, Berkeley, CA 94720, USA
13Aryabhatta Research Institute of Observational Sciences(ARIES), Manora Peak, Nainital, 263 002, India
14Department of Immunology, Uppsala University, Uppsala, Sweden
15Stellar Physics Department, Crimean Astrophysical Observatory, 298409, Nauchnyj, Crimea
16Department of Physics & Astronomy, University of North Carolina at Chapel Hill, NC 27599-3255, USA
17Main Astronomical Observatory of the NAS of Ukraine, 27, Akademik Zabolotny St., Kyiv, 03143, Ukraine
18Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham DH1 3LE, UK
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.8 MB)
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Language: English
Published: IOP Publishing, 2020
Publish Date: 2019-12-20


In this paper we report the current status of a new research program. The primary goal of the "Vanishing and Appearing Sources during a Century of Observations" project is to search for vanishing and appearing sources using existing survey data to find examples of exceptional astrophysical transients. The implications of finding such objects extend from traditional astrophysics fields to the more exotic searches for evidence of technologically advanced civilizations. In this first paper we present new, deeper observations of the tentative candidate discovered by Villarroel et al. in 2016. We then perform the first searches for vanishing objects throughout the sky by comparing 600 million objects from the US Naval Observatory Catalogue (USNO) B1.0 down to a limiting magnitude of ~20–21 with the recent Pan-STARRS Data Release-1 (DR1) with a limiting magnitude of ~23.4. We find about 150,000 preliminary candidates that do not have any Pan-STARRS counterpart within a 30'' radius. We show that these objects are redder and have larger proper motions than typical USNO objects. We visually examine the images for a subset of about 24,000 candidates, superseding the 2016 study with a sample 10 times larger. We find about 100 point sources visible in only one epoch in the red band of the USNO, which may be of interest in searches for strong M-dwarf flares, high-redshift supernovae, or other categories of unidentified red transients.

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Series: The astronomical journal
ISSN: 0004-6256
ISSN-E: 1538-3881
ISSN-L: 0004-6256
Volume: 159
Issue: 1
Article number: 8
DOI: 10.3847/1538-3881/ab570f
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Copyright information: © 2019. The American Astronomical Society. All rights reserved.