J/ApJ/844/L4 PS1 RRab stars for tracing outer Virgo overdensity (Sesar+, 2017)
The >100kpc distant spur of the Sagittarius stream and the outer Virgo
overdensity, as seen in PS1 RR Lyrae stars.
Sesar B., Hernitschek N., Dierickx M.I.P., Fardal M.A., Rix H.-W.
<Astrophys. J., 844, L4 (2017)>
=2017ApJ...844L...4S 2017ApJ...844L...4S
ADC_Keywords: Stars, variable ; Photometry ; Stars, distances ; Optical
Keywords: Galaxy: halo ; Galaxy: stellar content ; Galaxy: structure ;
stars: variables: RR Lyrae
Abstract:
We report the detection of spatially distinct stellar density features
near the apocenters of the Sagittarius (Sgr) stream's main leading and
trailing arm. These features are clearly visible in a high-fidelity
stellar halo map that is based on RR Lyrae from Pan-STARRS1: there is
a plume of stars 10kpc beyond the apocenter of the leading arm, and
there is a "spur" extending to 130kpc, almost 30kpc beyond the
previously detected apocenter of the trailing arm. Such an apocenter
substructure is qualitatively expected in any Sgr stream model, as
stars stripped from the progenitor at different pericenter passages
become spatially separated there. The morphology of these new Sgr
stream substructures could provide much-needed new clues and
constraints for modeling the Sgr system, including the level of
dynamical friction that Sgr has experienced. We also report the
discovery of a new, presumably unrelated halo substructure at 80kpc
from the Sun and 10° from the Sgr orbital plane, which we dub the
outer Virgo overdensity.
Description:
Our analysis uses a sample of highly probable type ab RR Lyrae stars,
selected from the Sesar+ (2017, J/AJ/153/204) catalog of PS1 RR Lyrae
stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 57 73 Outer Virgo overdensity (outer VOD) PS1 RR Lyrae
stars
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See also:
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
J/AJ/136/1645 : Spectroscopy of bright QUEST RR Lyrae stars (Vivas+, 2008)
J/ApJ/691/306 : Photom. of RR Lyrae candidates in Virgo stream (Prior+, 2009)
J/ApJ/708/717 : Light curve templates of RR Lyrae stars (Sesar+, 2010)
J/ApJ/765/154 : RR Lyrae stars in the Catalina Sky Survey (Drake+, 2013)
J/ApJ/817/73 : QSOs and RR Lyrae in Pan-STARRS1 3π Data (Hernitschek+ 2016)
J/ApJ/831/165 : RR Lyrae as tracers in Virgo overdensity region (Vivas+, 2016)
J/AJ/153/204 : RR Lyrae stars from the PS1 3π survey (Sesar+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg [197.6/217.6] Right ascension (J2000)
11- 19 F9.5 deg DEdeg [-11.2/-2.1] Declination (J2000)
21- 24 F4.2 --- Score [0.8/1] Final RRab classification score (1)
26- 30 F5.2 mag DM [19/19.9] Distance modulus (2)
32- 43 F12.10 d Per [0.4/0.8] Period
45- 52 F8.5 d Phi0 [-0.5/0.5] Phase offset (3)
54- 57 F4.2 mag rAmp [0.2/1.2] PS1 r-band light curve amplitude
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Note (1): Score>0.8 returns a sample with 90% purity and 80% completeness;
see section 5.2 in Sesar et al. (2017, J/AJ/153/204).
Note (2): The uncertainty in distance modulus is 0.06(rnd) ±0.03(sys) mag.
Note (3): See Equation 2 of Sesar et al. (2017, J/AJ/153/204)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Mar-2018