J/AJ/159/8 Vanishing and appearing sources using USNO data (Villarroel+, 2020)
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".
Villarroel B., Soodla J., Comeron S., Mattsson L., Pelckmans K.,
Lopez-Corredoira M., Krisciunas K., Guerras E., Kochukhov O., Bergstedt J.,
Buelens B., Bar R.E., Cubo R., Enriquez J.E., Gupta A.C., Imaz I.,
Karlsson T., Prieto M.A., Shlyapnikov A.A., de Souza R.S., Vavilova I.B.,
Ward M.J.
<Astron. J., 159, 8 (2020)>
=2020AJ....159....8V 2020AJ....159....8V (SIMBAD/NED BibCode)
ADC_Keywords: Positional data ; Magnitudes ; Surveys
Keywords: Astrobiology - Photographic photometry - Surveys -
Transient sources - Gamma-ray transient sources
Abstract:
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. (2016AJ....152...76V 2016AJ....152...76V). 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 (Cat. I/284) down to
a limiting magnitude of ∼20-21 with the recent Pan-STARRS Data Release-1
(DR1, Cat. II/349) with a limiting magnitude of ∼23.4. We find about
150000 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 24000 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.
Description:
We examine the final 1691 candidates and compare the old and new images
between the DSS1 and the SDSS, complementing the study with images in
several bands in the STScI archive when the DSS1 images were not clear
enough. At this stage, most of the candidates are the result of slightly
offset coordinates, and the images reveal that the objects are present
in both old and new images, with tiny offsets of the central point. About
200 of the 1691 candidates are caused by dead stripes in the SDSS.
Finally, about 100 candidates remain, most with a point-like appearance.
Nearly all these candidates are single-epoch observations in the
Palomar Sky Survey (POSS-I), red band.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 30 99 Coordinates (J2000.0) of the first set of
∼100 surviving candidates
table3.dat 24 28 The most interesting candidates
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See also:
I/284 : The USNO-B1.0 Catalog (Monet+, 2003)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers, 2016)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Hour of Right Ascension (J2000)
4- 5 I2 min RAm Minute of Right Ascension (J2000)
7- 11 F5.2 s RAs Second of Right Ascension (J2000)
13 A1 --- DE- Sign of the Declination (J2000)
14- 15 I2 deg DEd Degree of Declination (J2000)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000)
20- 24 F5.2 arcsec DEs Arcsecond of Declination (J2000)
26- 30 F5.2 mag rmag [13.57/19.49] r band magnitude (1)
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Note (1): The listed red magnitudes (first epoch) from USNO may suffer from
large uncertainties due to the issues in photometry.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Hour of Right Ascension (J2000) (1)
4- 5 I2 min RAm Minute of Right Ascension (J2000) (1)
7- 11 F5.2 s RAs Second of Right Ascension (J2000) (1)
13 A1 --- DE- Sign of the Declination (J2000) (1)
14- 15 I2 deg DEd Degree of Declination (J2000) (1)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000) (1)
20- 24 F5.2 arcsec DEs Arcsecond of Declination (J2000) (1)
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Note (1): For the events listed in Table 2, we remeasured the coordinates of
the interesting candidates. The list contains all events showing a single
point source with r<18.4, either as measured by the listed USNO magnitudes or
when we remeasured its magnitude directly from the digitalized plates. Also
one object that appears to be seen in more than one image is included.
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 07-Feb-2020