J/A+A/527/A77 NGC 1893 optical and NIR photometry (Prisinzano+, 2011)
Star formation in the outer Galaxy: membership and fundamental parameters of the
young open cluster NGC 1893.
Prisinzano L., Sanz-Forcada J., Micela G., Caramazza M., Guarcello M.G.,
Sciortino S., Testi L.
<Astron. Astrophys. 527, A77 (2011)>
=2011A&A...527A..77P 2011A&A...527A..77P
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Photometry, infrared ;
Photometry, millimetric/submm
Keywords: open clusters and associations: individual: NGC 1893 -
stars: pre-main sequence - stars: formation -
Hertzsprung-Russell and C-M diagrams - infrared: stars
Abstract:
Different environmental conditions can play a crucial role in
determining final products of the star formation process and in this
context, less favorable activities of star formation are expected in
the external regions of our Galaxy. We studied the properties of the
young open cluster NGC 1893 located about 12kpc from the galactic
center, to investigate how different physical conditions can affect
the process of star formation. By adopting a multiwavelength approach,
we compiled a catalog extending from X-rays to NIR data to derive the
cluster membership. In addition, optical and NIR photometric
properties are used to evaluate the cluster parameters. We find
415 diskless candidate members plus 1061 young stellar objects with
a circumstellar disk or class II candidate members, 125 of which are
also Hα emitters. Considering the diskless candidate members,
we find that the cluster distance is 3.6±0.2kpc and the mean
interstellar reddening is E(B-V)=0.6±0.1 with evidence of
differential reddening in the whole surveyed region. NGC 1893 contains
a conspicuous population of pre-main sequence stars together with the
well studied main sequence cluster population; we found a disk
fraction of about 70% similar to that found in clusters of similar
age in the solar neighbor and then, despite expected unfavorable
conditions for star formation, we conclude that very rich young
clusters can form also in the outer regions of our Galaxy.
Description:
We present new optical and NIR photometric data in the VRIJHK and
H-α bands for the cluster NGC 1893. The optical photometry was
obtained by using images acquired in service mode using two different
telescopes: the Device Optimized for the LOw RESolution (DOLORES)
mounted on the Telescopio Nazionale Galileo (TNG), used in service
mode during three nights in 2007, and the Calar Alto Faint Object
Spectrograph (CAFOS), mounted on the 2.2m telescope in Calar Alto
German-Spanish Observatory (Spain), during three nights in 2007 and
2008. NIR observations were acquired in service mode at the TNG, using
the large field Near Infrared Camera Spectrometer (NICS) with the
Js(1.25um), H(1.63um) and K'(2.12um) filters during eight nights in
2007 and 2008. We observed a field around NGC 1893 with a raster of
4x4 pointings, at each pointing we obtained a series of NINT dithered
exposures. Each exposure is a repetition of a DIT (Detector Integration
Time) times NDIT (number of DIT), to avoid saturation of the background.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 76 1068 VRI H-α magnitudes of Class 0/I/II candidate
members
table6.dat 76 415 VRI H-α magnitudes of diskless candidate
members
table7.dat 117 1068 Infrared magnitudes of Class 0/I/II candidate
members
table8.dat 117 415 Infrared magnitudes of diskless candidate members
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See also:
J/A+A/488/211 : Infrated photometry of NGC 1893 (Caramazza+, 2008)
Byte-by-byte Description of file: table5.dat table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID Sequential number
6- 9 I4 --- XID ? Designation from Caramazza et al.
(2011, in prep.)
11- 20 F10.7 deg RAdeg Right ascension (J2000.0)
22- 31 F10.7 deg DEdeg Declination (J2000.0)
33- 38 F6.3 mag Vmag ? Landolt V magnitude
40- 44 F5.3 mag e_Vmag ? Error of the Landolt V magnitude
46- 51 F6.3 mag Rmag ? Landolt R magnitude
53- 57 F5.3 mag e_Rmag ? Error of the Landolt R magnitude
59- 64 F6.3 mag Icmag ? Cousins I magnitude
66- 70 F5.3 mag e_Icmag ? Error of the Cousins I magnitude
72- 76 F5.3 mag Hamag ? H-α magnitude
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Byte-by-byte Description of file: table7.dat table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID Sequential number
6- 15 F10.7 deg RAdeg Right ascension (J2000.0)
17- 26 F10.7 deg DEdeg Declination (J2000.0)
28- 33 F6.3 mag Jmag ? TNG/NICS Js magnitude
35- 39 F5.3 mag e_Jmag ? Error in Jmag
41- 46 F6.3 mag Hmag ? TNG/NICS H magnitude
48- 52 F5.3 mag e_Hmag ? Error in Hmag
54- 59 F6.3 mag Kmag ? TNG/NICS K' magnitude
61- 65 F5.3 mag e_Kmag ? Error in Kmag
67- 72 F6.3 mag [3.6] ? Magnitude at 3.6um
74- 78 F5.3 mag e_[3.6] ? Error in [3.6] magnitude
80- 85 F6.3 mag [4.5] ? Magnitude at 4.5um
87- 91 F5.3 mag e_[4.5] ? Error in [4.5] magnitude
93- 98 F6.3 mag [5.8] ? Magnitude at 5.8um
100-104 F5.3 mag e_[5.8] ? Error in [5.8] magnitude
106-111 F6.3 mag [8.0] ? Magnitude at 8.0um
113-117 F5.3 mag e_[8.0] ? Error in [8.0] magnitude
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Acknowledgements:
Loredana Prisinzano, loredana(at)astropa.inaf.it
(End) Patricia Vannier [CDS] 20-Oct-2010