J/MNRAS/478/3809 TGAS distances (Schonrich+, 2018)
Warp, waves, and wrinkles in the Milky Way.
Schonrich R., Dehnen W.
<Mon. Not. R. Astron. Soc., 478, 3809-3824 (2018)>
=2018MNRAS.478.3809S 2018MNRAS.478.3809S (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, nearby ; Stars, distances ; Optical
Keywords: stars: distances - stars: kinematics and dynamics -
stars: statistics - Galaxy: kinematics and dynamics -
Solar neighbourhood - Galaxy: structure
Abstract:
We derive unbiased distance estimates for the Gaia-TGAS data set by
correcting for the bias due to the distance dependence of the
selection function, which we measure directly from the data. From
these distances and proper motions, we estimate the vertical and
azimuthal velocities, W and Vφ, and angular momentum Lz for
stars in the Galactic centre and anticentre directions. The resulting
mean vertical motion W- hows a linear increase with both Vφ
and Lz at 10σ significance. Such a trend is expected from and
consistent with the known Galactic warp. This signal extends to stars
with guiding centre radii Rg<R0, placing the onset of the warp at
R≤7kpc. At equally high significance, we detect a previously unknown
wave-like pattern of W- over guiding centre Rg with an amplitude
∼1km/s and a wavelength ∼2.5kpc. This pattern is present in both the
centre and anticentre directions, consistent with a winding
(corrugated) warp or bending wave, likely related to known features in
the outer disc (TriAnd and Monoceros overdensities), and may be caused
by the interaction with the Sgr dwarf galaxy ∼1Gyr ago. The only
significant deviation from this simple fit is a stream-like feature
near Rg∼9kpc (|Lz|∼2150kpc.km/s).
Description:
We have derived distances to TGAS stars in Gaia DR1, which, unlike
most previous attempts, are by construction unbiased in the mean
estimated distance. We have used these distances in conjunction with
the TGAS proper motions to measure the kinematic signal of bending
modes (including the warp) of the Milky Way disc in the mean vertical
stellar motions. To derive unbiased distances for Gaia-TGAS stars, we
have measured an effective spatial selection function for this sample,
which is very well described by a simple declining exponential with a
scale length 0.2kpc.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tgasdist.dat 109 1037080 TGAS distance catalog
--------------------------------------------------------------------------------
See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
Byte-by-byte Description of file: tgasdist.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- SolID Gaia DR1 Solution ID
21- 39 I19 --- GaiaDR1 Gaia DR1 Source ID
41- 49 F9.5 mag Plx Gaia DR1 Absolute barycentric stellar parallax
51- 58 F8.6 mag e_Plx Gaia DR1 Absolute barycentric stellar parallax
error
60- 73 F14.9 deg GLON [-180/180] Galactic longitude
75- 86 E12.9 deg GLAT [-90/90] Galactic latitude
88- 97 F10.8 kpc Dist Expected distance
99-109 E11.9 kpc e_Dist Expected distance error
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Sep-2021