J/ApJ/731/4 Galactic halo as seen by the CFHTLS (Sesar+, 2011)
The shape and profile of the Milky Way halo as seen by the Canada-France-Hawaii
Telescope Legacy Survey.
Sesar B., Juric M., Ivezic Z.
<Astrophys. J., 731, 4 (2011)>
=2011ApJ...731....4S 2011ApJ...731....4S
ADC_Keywords: Photometry, SDSS ; Stars, halo ; Surveys
Keywords: Galaxy: halo - Galaxy: stellar content - Galaxy: structure -
stars: statistics
Abstract:
We use Canada-France-Hawaii Telescope Legacy Survey data for
170deg2, recalibrated and transformed to the Sloan Digital Sky
Survey ugri photometric system, to study the distribution of
near-turnoff main-sequence stars in the Galactic halo along four lines
of sight to heliocentric distances of ∼35kpc. We find that the halo
stellar number density profile becomes steeper at Galactocentric
distances greater than Rgal∼28kpc, with the power-law index changing
from ninner=-2.62±0.04 to nouter=-3.8±0.1. In particular, we
test a series of single power-law models and find them to be strongly
disfavored by the data. The parameters for the best-fit Einasto
profile are n=2.2±0.2 and Re=22.2±0.4kpc. We measure the
oblateness of the halo to be q=c/a=0.70±0.01 and detect no evidence
of it changing across the range of probed distances. The Sagittarius
stream is detected in the l=173° and b=-62° direction as an
overdensity of [Fe/H]~-1.5dex stars at Rgal∼32kpc, providing a new
constraint for the Sagittarius stream and dark matter halo models. We
also detect the Monoceros stream as an overdensity of [Fe/H]>-1.5dex
stars in the l=232° and b=26° direction at Rgal≲25kpc. In
the two sight lines where we do not detect significant substructure,
the median metallicity is found to be independent of distance within
systematic uncertainties ([Fe/H]~-1.5±0.1dex).
Description:
The astrometry in these catalogs is accurate to within 0.2" relative
to external reference frames (Gwyn 2008PASP..120..212G 2008PASP..120..212G). The catalogs
are available for each pointing (a pointing is ∼1deg2 part of a
CFHTLS field) through the Canadian Astronomy Data Centre (CADC) Web
site.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 34 171 Δtotalj,f values for the CFHTLS fields
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See also:
II/317 : The CFHTLS Survey (T0007 release) (Hudelot+ 2012)
J/A+A/509/A81 : Candidate clusters detected in six CFHTLS fields (Adami+,
2010)
J/A+A/494/845 : Galaxy clusters in the CFHTLS (Grove+, 2009)
J/ApJ/633/630 : Low-mass stars found in CFHTLS (Willott+, 2005)
http://www1.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/community/CFHTLS-SG/docs/
cfhtlswide.html : CFHTLS Wide Field stacked images and catalogues
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Point Pointing identification (1)
7 A1 --- f_i' [*] i'2 band used (2)
9- 13 F5.3 mag u* The u* band Δtotalj,f value (3)
15- 20 F6.3 mag g' The g' band Δtotalj,f value (3)
22- 27 F6.3 mag r' The r' band Δtotalj,f value (3)
29- 34 F6.3 mag i' The i' band Δtotalj,f value (3)
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Note (1): Where the first two bytes give the CFHTLS field as given in table 1:
------------------------------------------------------------------------
CFHTLS Field RA (J2000) DEC (deg) GLON (deg) GLAT (deg) Sky Coverage
------------------------------------------------------------------------
W1 34.5 -7.0 173.12 -61.59 72
W2 134.5 -3.3 231.78 26.04 25
W3 214.4 54.5 98.70 58.47 49
W4 333.3 1.3 63.32 -41.84 25
------------------------------------------------------------------------
Note (2):
* = used the i'2 band instead of i' (The i'2 filter is the new CFHT
filter that was installed after the i' filter broke in 2007 October).
Note (3): Where Δtotj,f is the total correction for the jth
pointing in the f field. See section 2.3.3.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 12-Oct-2012