J/ApJ/807/5 R-band polarimetry data in the region of Lupus I (Franco+, 2015)
Tracing the magnetic field morphology of the Lupus I molecular cloud.
Franco G.A.P., Alves F.O.
<Astrophys. J., 807, 5 (2015)>
=2015ApJ...807....5F 2015ApJ...807....5F (SIMBAD/NED BibCode)
ADC_Keywords: Polarization ; Molecular clouds ; Photometry, infrared
Keywords: ISM: clouds; ISM: individual: Lupus I;
ISM: magnetic fields; techniques: polarimetric
Abstract:
Deep R-band CCD linear polarimetry collected for fields with lines of
sight toward the Lupus I molecular cloud is used to investigate the
properties of the magnetic field within this molecular cloud. The
observed sample contains about 7000 stars, almost 2000 of them with a
polarization signal-to-noise ratio larger than 5. These data cover
almost the entire main molecular cloud and also sample two diffuse
infrared patches in the neighborhood of Lupus I. The large-scale
pattern of the plane-of-sky projection of the magnetic field is
perpendicular to the main axis of Lupus I, but parallel to the two
diffuse infrared patches. A detailed analysis of our polarization data
combined with the Herschel/SPIRE 350µm dust emission map shows that
the principal filament of Lupus I is constituted by three main clumps
that are acted on by magnetic fields that have different large-scale
structural properties. These differences may be the reason for the
observed distribution of pre- and protostellar objects along the
molecular cloud and the cloud's apparent evolutionary stage. On the
other hand, assuming that the magnetic field is composed of
large-scale and turbulent components, we find that the latter is
rather similar in all three clumps. The estimated plane-of-sky
component of the large-scale magnetic field ranges from about 70 to
200µG in these clumps. The intensity increases toward the Galactic
plane. The mass-to-magnetic flux ratio is much smaller than unity,
implying that Lupus I is magnetically supported on large scales.
Description:
The polarimetric data were collected with the 1.6m and the IAG 60cm
telescopes at the Observatorio do Pico dos Dias (LNA/MCTI, Brazil) in
missions conducted on several nights from 2004 to 2008.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 125 7008 Polarimetric data obtained for Lupus I
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See also:
VI/139 : Herschel Observation Log (Herschel Science Centre, 2013)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/569/L1 : Polarization hole in a starless core (Alves+, 2014)
J/PASJ/63/S1 : Atlas of dark clouds based on 2MASS (Dobashi+, 2011)
J/ApJS/177/551 : Spitzer c2d survey of Lupus dark clouds (Merin+, 2008)
J/ApJ/603/584 : Polarimetry toward Musca dark cloud (Pereyra+, 2004)
J/MNRAS/331/474 : ubvyβ photometry in the Lupus dark cloud (Franco, 2002)
http://www.herschel.fr/cea/gouldbelt/en/ : Gould Belt survey web page
http://darkclouds.u-gakugei.ac.jp/ : Dark clouds extinction maps
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Running sequence number
7- 8 I2 h RAh [15] Hour of Right Ascension (J2000)
10- 11 I2 min RAm [36/48] Minute of Right Ascension (J2000)
13- 17 F5.2 s RAs Second of Right Ascension (J2000)
20 A1 --- DE- [-] Sign of the Declination (J2000)
21- 22 I2 deg DEd [33/35] Degree of Declination (J2000)
24- 25 I2 arcmin DEm Arcminute of Declination (J2000)
27- 30 F4.1 arcsec DEs Arcsecond of Declination (J2000)
33- 40 F8.4 deg GLON Longitude in Galactic coordinate
43- 49 F7.4 deg GLAT Latitude in Galactic coordinate
52- 57 F6.3 % Pol [0.01/11.1] Degree of polarization (P) in R-band
61- 65 F5.3 % e_Pol Measured uncertainty in Pol
69- 73 F5.3 % s_Pol Theoretical uncertainty in Pol
76- 80 F5.1 deg Theta Polarization position angle
(measured from north to east)
83- 88 F6.3 mag Jmag [6.5/17.2] J magnitude (from 2MASS catalogue)
90- 95 F6.3 mag e_Jmag [0.01/0.6]? Uncertainty in Jmag
98-103 F6.3 mag Hmag [5.8/17.8] H magnitude (from 2MASS catalogue)
105-110 F6.3 mag e_Hmag [0.02/0.5]? Uncertainty in Hmag
113-118 F6.3 mag Kmag [5.5/17.2] K magnitude (from 2MASS catalogue)
120-125 F6.3 mag e_Kmag [0.01/0.7]? Uncertainty in Kmag
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Acknowledgements:
Gabriel Armando P. Franco [Instituto de Ciencias Exatas (ICEx),
Universidade Federal de Minas Gerais (UFMG)]
(End) Emmanuelle Perret [CDS] 30-Nov-2015