J/ApJ/754/101 Monoceros Overdensity deep imaging with Subaru (Conn+, 2012)
Slicing the Monoceros Overdensity with SUPRIME-CAM.
Conn B.C., Noel N.E.D., Rix H.-W., Lane R.R., Lewis G.F., Irwin M.J.,
Martin N.F., Ibata R.A., Dolphin A., Chapman S.
<Astrophys. J., 754, 101 (2012)>
=2012ApJ...754..101C 2012ApJ...754..101C
ADC_Keywords: Photometry, ugriz ; Extinction ; Milky Way ; Associations, stellar
Keywords: Galaxy: disk; Galaxy: structure
Abstract:
We derive distance, density, and metallicity distribution of the
stellar Monoceros Overdensity (MO) in the outer Milky Way, based on
deep imaging with the Subaru Telescope. We applied color-magnitude
diagram fitting techniques in three stripes at galactic longitudes,
l∼130°, 150°, 170°, and galactic latitudes,
+15°≤b≤+25°. The MO appears as a wall of stars at a
heliocentric distance of ∼10.1±0.5kpc across the observed longitude
range with no distance change. The MO stars are more metal-rich
([Fe/H]~-1.0) than the nearby stars at the same latitude. These data
are used to test three different models for the origin of the MO: a
perturbed disk model, which predicts a significant drop in density
adjacent to the MO that is not seen; a basic flared disk model, which
can give a good match to the density profile but the MO metallicity
implies the disk is too metal-rich to source the MO stars; and a tidal
stream model, which, from the literature, brackets the distances and
densities we derive for the MO, suggesting that a model can be found
that would fully fit the MO data. Further data and modeling will be
required to confirm or rule out the MO feature as a stream or as a
flaring of the disk.
Description:
The data were collected using the SUPRIME-CAM Wide Field Imager on the
Subaru Telescope in Hawaii, in 2007 November 9 and 2008 January 1.
Roughly 180 frames were taken in two filters, Sloan g and r, and
arranged into the three stripes across the thick disk of the Galaxy
(see Figure 1).
Mean magnitude at the 50% completeness level (mc) and typical width
of the rollover function (λ) for each filter (table 2):
--------------------------------------------------
Region mc (g0) mc (r0) λ
--------------------------------------------------
130 stripe 24.2 23.2 0.73
150 stripe 24.8 23.8 0.55
170 stripe 25.0 24.2 0.70
--------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
mo130.dat 116 805560 *The l=130° stripe catalog
mo150.dat 116 1158878 *The l=150° stripe catalog
mo170.dat 116 1446603 *The l=170° stripe catalog
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Notes on mo130.dat, mo150.dat and mo170.dat: The data here have been extinction
corrected following the standard prescription when the extinction is less
than E(B-V)≤0.1, otherwise the relation from Bonifacio et al.
(2000AJ....120.2065B 2000AJ....120.2065B), as shown in Equation (A1), has been used. The data have
also been corrected for airmass. Users should note that duplicate observations
of the same object (in overlap regions) have not been removed from the
catalog. See Appendix section for further details.
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See also:
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
J/MNRAS/419/2844 : RAVE-DR3 radial metallicity gradient (Coskunoglu+, 2012)
J/ApJ/731/4 : Galactic halo as seen by the CFHTLS (Sesar+, 2011)
J/ApJ/588/824 : Velocities of blue stars near (l,b)=(198,-27) (Yanny+, 2003)
Byte-by-byte Description of file: mo130.dat mo150.dat mo170.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 declination (J2000)
14- 15 I2 deg DEd Degree of declination (J2000)
17- 18 I2 arcmin DEm Arcminute of declination (J2000)
20- 23 F4.1 arcsec DEs Arcsecond of declination (J2000)
25- 34 F10.6 deg GLON Galactic longitude
36- 44 F9.6 deg GLAT Galactic latitude
46- 47 I2 --- chip [1/10] Subaru/SUPRIME-CAM chip number
49- 54 F6.1 --- xpixg X pixel (g-band)
56- 61 F6.1 --- ypixg Y pixel (g-band)
63- 68 F6.3 mag gmag [-7/40.6] SUPRIME-CAM g-band magnitude
70- 75 F6.3 mag e_gmag [0/9] gmag uncertainty
77- 78 I2 --- gcl [-9/1]? gmag classification flag (1)
80- 85 F6.1 --- xpixr X pixel (r-band)
87- 92 F6.1 --- ypixr Y pixel (r-band)
94-100 F7.3 mag rmag [-12.3/45.2] SUPRIME-CAM r-band magnitude
102-107 F6.3 mag e_rmag [0/8] rmag uncertainty
109-110 I2 --- rcl [-9/1]? rmag classification flag (1)
112-116 F5.3 mag E(B-V) [0.03/0.9] Extinction E(B-V)
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Note (1): The classification scheme is as follows:
-1 = stellar,
-2 = possible stellar,
1 = non-stellar/galaxy,
0 = noise,
-3 = possible non-stellar/galaxy,
-8 = cross-match problem,
-9 = saturated object.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 04-Mar-2014