J/A+A/557/A82 Near-IR polarimetry of Galactic center sources (Buchholz+, 2013)
Ks- and Lp-band polarimetry on stellar and bow-shock sources in the
Galactic Center.
Buchholz R.M., Witzel G., Schodel R., Eckart A.
<Astron. Astrophys. 557, A82 (2013)>
=2013A&A...557A..82B 2013A&A...557A..82B
ADC_Keywords: Stars, nearby ; Infrared sources ; Photometry, infrared ;
Polarization
Keywords: Galaxy: center - polarization - dust, extinction -
infrared: stars
Abstract:
Infrared observations of the Galactic center (GC) provide a unique
opportunity to study stellar and bow-shock polarization effects in a
dusty environment.
The goals of this work are to present new Ks- and Lp-band polarimetry
on an unprecedented number of sources in the central parsec of the GC,
thereby expanding our previous results in the H- and Ks-bands.
We use AO-assisted Ks- and Lp-band observations, obtained at the ESO
VLT. High precision photometry and the new polarimetric calibration
method for NACO allow us to map the polarization in a region of
8"x25" (Ks) resp. 26"x28" (Lp). These are the first polarimetric
observations of the GC in the Lp-band in 30 years, with vastly
improved spatial resolution compared to previous results. This allows
resolved polarimetry on bright bow-shock sources in this area for the
first time at this wavelength.
Description:
This table contains the H-, Ks-, and Lp-band polarization of sources
in the Galactic Center. For each source, the offset in Right Ascension
and Declination as well as the projected distance from Sgr A* are
given (in arcsec). The table also lists the source brightness in
magnitudes in the H-, Ks-, and Lp-band for orientation. This table
contains the data obtained in our previous study, Buchholz et al. 2011
(J/A+A/534/A117), in addition to the new results. Not every source is
contained in all data-sets (one H-band, three Ks-band with different
fields-of-view, one Lp-band). Entries with the value " - " indicate
that the source is not contained in the respective data-set.
Polarization degrees are given in percent, polarization angles in
degrees. The data is combined from different epochs, so a small number
of very fast moving sources may be listed separately for each
data-set.
Objects:
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RA (2000) DE Designation(s)
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17 45 40.04 -29 00 28.2 SgrA* = NAME Sgr A*
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
pollist.dat 130 557 H, Ks and Lp-band polarization parameters (tableA1)
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See also:
J/A+A/499/483 : sources in galactic center NIR observations (Buchholz+, 2009)
J/A+A/502/91 : Proper motions of stars near SgrA* (Schoedel+, 2009)
J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010)
J/ApJ/727/L36 : 1.3mm VLBI observations of Sagittarius A* (Fish+, 2011)
J/A+A/534/A117 : NIR polarimetry of sources near SgrA* (Buchholz+, 2011)
Byte-by-byte Description of file: pollist.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Source number
5- 10 F6.2 arcsec oRA Right ascension offset from Sgr A* (1)
12- 17 F6.2 arcsec oDE Declination offset from Sgr A* (1)
19- 23 F5.2 arcsec Rp Projected distance from Sgr A*
25- 28 F4.1 mag Ksmag ?=- Apparent Ks-band magnitude
30- 32 F3.1 mag e_Ksmag ?=- Error of Ks-band magnitude
34- 37 F4.1 mag Hmag ?=- Apparent H-band magnitude
39- 41 F3.1 mag e_Hmag ?=- Error of H-band magnitude
43- 46 F4.1 mag Lpmag ?=- Apparent Lp-band magnitude
48- 50 F3.1 mag e_Lpmag ?=- Error of Lp-band magnitude
52- 55 F4.1 % pK1 ?=- Ks-band polarization degree (2)
57- 59 F3.1 % e_pK1 ?=- Error of pK1
61- 63 I3 % PAK1 [-90/90]?=- K-band polarization angle
65- 66 I2 % e_PAK1 ?=- Error of PAK1
68- 71 F4.1 % pK2 ?=- K-band polarization degree (2)
73- 75 F3.1 % e_pK2 ?=- Error of pK2
77- 79 I3 % PAK2 [-90/90]?=- K-band polarization angle
81- 82 I2 % e_PAK2 ?=- Error of PAK2
84- 87 F4.1 % pK3 ?=- K-band polarization degree (2)
89- 91 F3.1 % e_pK3 ?=- Error of pK3
93- 95 I3 deg PAK3 [-90/90]?=- K-band polarization angle
97- 98 I2 deg e_PAK3 ?=- Error of PAK3
100-103 F4.1 % pH ?=- H-band polarization degree (2)
105-107 F3.1 % e_pH ?=- Error of pH
109-111 I3 deg PAH [-90/90]?=- H-band polarization angle
113-114 I2 deg e_PAH ?=- Error of PAH
116-119 F4.1 % pLp ?=- Lp-band (3.5µm) polarization degree (2)
121-123 F3.1 % e_pLp ?=- Error of pLp
125-127 I3 deg PALp [-90/90]?=- Lp-band polarization angle
129-130 I2 deg e_PALp ?=- Error of PALp
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Note (1): Offsets from SgrA* at 17:45:40.036-29:00:28.17 (J2000).
Note (2): the observations dates are:
H = 2004-06-12 (30 exposures)
K1 = 2009-05-18 (143 exposures)
K2 = 2007-04-03 (70 exposures)
K3 = 2011-03-19 (37 exposures)
L = 2011-03-17 (26 exposures)
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Acknowledgements:
Dr. Rainer M. Buchholz, Rainer_Buchholz2001(at)yahoo.de
Universita zu Kon, Germany
(End) Rainer Buchholz [Univ. zu Koln], Patricia Vannier [CDS] 10-Sep-2013