J/AJ/145/32 AKARI-LMC Near-infrared Spectroscopic Catalog (Shimonishi+, 2013)
AKARI Infrared Camera Survey of the Large Magellanic Cloud.
II. The near-infrared spectroscopic catalog.
Shimonishi T., Onaka T., Kato D., Sakon I., Ita Y., Kawamura A., Kaneda H.
<Astron. J., 145, 32 (2013)>
=2013AJ....145...32S 2013AJ....145...32S
ADC_Keywords: Magellanic Clouds ; Infrared sources ; Spectra, infrared
Mission_Name: AKARI
Keywords: catalogs, infrared: stars, Magellanic Clouds, surveys
techniques: spectroscopic
Abstract:
We performed a near-infrared spectroscopic survey toward an area of
∼10deg2 of the Large Magellanic Cloud (LMC) with the infrared
satellite AKARI. Observations were carried out as part of the AKARI
Large-area Survey of the Large Magellanic Cloud (LSLMC). The slitless
multi-object spectroscopic capability of the AKARI/IRC enabled us to
obtain low-resolution (R∼20) spectra in 2-5µm for a large number
of point sources in the LMC. As a result of the survey, we extracted
about 2000 infrared spectra of point sources. The data are organized
as a near-infrared spectroscopic catalog. The catalog includes various
infrared objects such as young stellar objects (YSOs), asymptotic
giant branch (AGB) stars, supergiants, and so on. It is shown that 97%
of the catalog sources have corresponding photometric data in the
wavelength range from 1.2 to 11µm, and 67% of the sources also
have photometric data up to 24µm. The catalog allows us to
investigate near-infrared spectral features of sources by comparison
with their infrared spectral energy distributions. In addition, it is
estimated that about 10% of the catalog sources are observed at more
than two different epochs. This enables us to study a spectroscopic
variability of sources by using the present catalog. Initial results
of source classifications for the LSLMC samples are presented. We
classified 659 LSLMC spectra based on their near-infrared spectral
features by visual inspection. As a result, it is shown that the
present catalog includes 7 YSOs, 160 C-rich AGBs, 8 C-rich AGB
candidates, 85 O-rich AGBs, 122 blue and yellow supergiants, 150 red
super giants, and 128 unclassified sources. Distributions of the
classified sources on the color-color and color-magnitude diagrams are
discussed in the text. Continuous wavelength coverage and high
spectroscopic sensitivity in 2-5µm can only be achieved by space
observations. This is an unprecedented large-scale spectroscopic
survey toward the LMC in the near-infrared. A large number of
near-infrared spectral data provided by the survey possess scientific
potential that can be applied to various studies. In this paper, we
present the details of the spectroscopic survey and the catalog, and
discuss its scientific applications.
Description:
This catalog contains the 2111 near-infrared spectra of point sources
in the Large Magellanic Cloud (LMC) with the Infrared Camera (IRC) on
board AKARI satellite on the phase 2. In this spectroscopic survey,
the slit-less prism multiobject spectroscopy mode was used to obtain
2-5 micron low- resolution (R∼20) spectra.
Since spectroscopic survey was performed by the slit-less
spectroscopy, an overlap of object's spectrum in the dispersion
direction makes an accurate extraction of spectral data very
difficult. The presence or absence of spectral overlapping for sources
is checked by using the IRC N3 imaging data (Kato et al., 2012, Cat.
J/AJ/144/179). The sources without spectral contamination or sources
with partial and weak contamination are selected in this catalog. The
catalog sources are matched with several photometric catalogs in the
literatures. See paper for details.
The IRC observations produce datasets with two different exposure
times in one observation, which are referred to as long- and
short-exposure data. Data users must be careful about the effect of
saturation in the spectra. The saturation limits of long- and short-
exposure observations are estimated to be ∼0.1 and ∼0.5-1.0Jy around
2.5-3.0µm, respectively. Thus it is recommended to check both
exposure data and consider to use short-exposure data especially for
bright or blue sources. It is also advised to use data at 2.5-5.0µm
for scientific purpose, because the spectral ranges of 2.0-2.5µm
and 5.0-5.5µmare difficult to calibrate accurately due to the steep
shape of the spectral response curve.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sourceli.dat 318 2111 Source list
sp/* . 4214 *Individual spectra as ascii files
png/* . 4208 *Individual spectra as images
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Note on sp/*: spectra are labelled FSlFID.SID.spc, FSsFID.SID_short.spc,
SSlFID.SID.spc and SSsFID.SID_short.spc for FS/long, FS/short,
SS/long and SS/short, respectively.
Note on png/*: files are labelled FSlFID.SID.png, FSsFID.SID_short.png,
SSlFID.SID.png and SSsFID.SID_short.spc for FS/long, FS/short,
SS/long and SS/short, respectively.
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See also:
II/305 : SAGE LMC and SMC IRAC Source Catalog (IPAC 2009)
J/PASP/122/683 : SAGE-Spec Spitzer legacy program (Kemper+, 2010)
J/AJ/144/179 : AKARI-LMC Point-source catalog (Kato+, 2012)
Byte-by-byte Description of file: sourceli.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- ID Source identifier (JHHMMSS.ss+DDMMSS.s),
from Kato et al., 2012, Cat. J/AJ/144/179
22- 28 I7 --- FID Frame ID (22xxxxx)
31- 33 I3 --- SID [0/419] Source ID in frame
36- 44 F9.6 deg RAdeg Right ascension (J2000)
47- 56 F10.6 deg DEdeg Declination (J2000)
59- 68 A10 "date" ObsDate Observation date (yyyy.mm.dd)
71- 72 A2 --- fc [FS SS] Contamination flag (Full or Short) (1)
73 A1 --- s1 [s] single spectrum only (2)
75- 78 I4 --- SSID [74/4777]?=-1 Matched SAGE-Spec source ID (3)
81- 86 F6.3 mag Jmag ?=99.999 2MASS J magnitude
89- 94 F6.3 mag e_Jmag ?=99.999 J magnitude error
97-102 F6.3 mag Hmag ?=99.999 2MASS H magnitude
105-110 F6.3 mag e_Hmag ?=99.999 H magnitude error
113-118 F6.3 mag Kmag ?=99.999 2MASS Ks magnitude
121-126 F6.3 mag e_Kmag ?=99.999 Ks magnitude error
129-134 F6.3 mag [3.6] ?=99.999 Spitzer/IRAC 3.6um magnitude
137-142 F6.3 mag e_[3.6] ?=99.999 B1 magnitude error
145-150 F6.3 mag [4.5] ?=99.999 Spitzer/IRAC 4.5um magnitude
153-158 F6.3 mag e_[4.5] ?=99.999 B2 magnitude error
161-166 F6.3 mag [5.8] ?=99.999 Spitzer/IRAC 5.8um magnitude
169-174 F6.3 mag e_[5.8] ?=99.999 B3 magnitude error
177-182 F6.3 mag [8.0] ?=99.999 Spitzer/IRAC 8.0um magnitude
185-190 F6.3 mag e_[8.0] ?=99.999 B4 magnitude error
193-198 F6.3 mag [24] ?=99.999 Spitzer/MIPS 24um magnitude
201-206 F6.3 mag e_[24] ?=99.999 M24 magnitude error
209-214 F6.3 mag [70] ?=99.999 Spitzer/MIPS 70um magnitude
217-222 F6.3 mag e_[70] ?=99.999 M70 magnitude error
225-230 F6.3 mag [160] ?=99.999 Spitzer/MIPS 160um magnitude
233-238 F6.3 mag e_[160] ?=99.999 M160 magnitude error
241-246 F6.3 mag N3 ?=99.999 AKARI/IRC N3 3.2um magnitude
249-254 F6.3 mag e_N3 ?=99.999 N3 magnitude error
257-262 F6.3 mag S7 ?=99.999 AKARI/IRC S7 7.0um magnitude
265-270 F6.3 mag e_S7 ?=99.999 S7 magnitude error
273-278 F6.3 mag S11 ?=99.999 AKARI/IRC S11 11.0um magnitude
281-286 F6.3 mag e_S11 ?=99.999 S11 magnitude error
289-294 F6.3 mag L15 ?=99.999 AKARI/IRC L15 15.0um magnitude
297-302 F6.3 mag e_L15 ?=99.999 L15 magnitude error
305-310 F6.3 mag L24 ?=99.999 AKARI/IRC L24 24.0um magnitude
313-318 F6.3 mag e_L24 ?=99.999 L24 magnitude error
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Note (1): Flag is FS or SS:
FS = a full 2.5-5.0um spectrum
SS = spectrum shorter than 5.0um
Note (2): All sources have two spectra, one in "short" and the other in
"long" exposure, except those marked with an * that have only one spectrum
in "long" exposure.
Note (3): SAGE-Spec catalog (J/PASP/122/683); non-matched sources are
represented by -1.
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Byte-by-byte Description of file: sp/*
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Bytes Format Units Label Explanations
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1- 5 F5.3 um lambda [2.0/5.5] Wavelength in micron
8- 13 F6.2 mJy Flux ?=- Observed NIR flux (1)
16- 21 F6.2 mJy b_Flux ?=- Lower value of Flux interval (1)
24- 29 F6.2 mJy B_Flux ?=- Upper value of Flux interval (1)
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Note (1): --- (NaN) value is allocated to unavailable data points (due to
saturation, spectral overlapping, truncation at the detector edge, etc.).
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History:
Copied at http://www.ir.isas.jaxa.jp/AKARI/Archive/Catalogues/LMCSPC_V1/
(End) Takashi Shimonishi [Kobe University], Patricia Vannier [CDS] 29-Nov-2013