J/AJ/151/146 IRS spectra with features of crystalline silicates (Chen+, 2016)
A systematic search for the spectra with features of crystalline silicates in
the Spitzer IRS enhanced products.
Chen R., Luo A., Liu J., Jiang B.
<Astron. J., 151, 146-146 (2016)>
=2016AJ....151..146C 2016AJ....151..146C (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Stars, variable ; Stars, pre-main sequence ;
Spectra, infrared ; Equivalent widths ; Spectral types ; Redshifts
Keywords: catalogs - circumstellar matter - infrared: ISM - infrared: stars -
ISM: lines and bands - stars: variables: T Tauri, Herbig Ae/Be
Abstract:
The crystalline silicate features are mainly reflected in infrared
bands. The Spitzer Infrared Spectrograph (IRS) collected numerous
spectra of various objects and provided a big database to investigate
crystalline silicates in a wide range of astronomical environments. We
apply the manifold ranking algorithm to perform a systematic search
for the spectra with crystalline silicate features in the Spitzer IRS
Enhanced Products available. In total, 868 spectra of 790 sources are
found to show the features of crystalline silicates. These objects are
cross-matched with the SIMBAD database as well as with the Large Sky
Area Multi-object Fiber Spectroscopic Telescope (LAMOST)/DR2 (Luo et al.
2016, Cat. V/149). The average spectrum of young stellar objects shows
a variety of features dominated either by forsterite or enstatite or
neither, while the average spectrum of evolved objects consistently
present dominant features of forsterite in AGB, OH/IR, post-AGB, and
planetary nebulae. They are identified optically as early-type stars,
evolved stars, galaxies and so on. In addition, the strength of
spectral features in typical silicate complexes is calculated. The
results are available through CDS for the astronomical community to
further study crystalline silicates.
Description:
Spectra taken by the IRS (Houck et al. 2004ApJS..154...18H 2004ApJS..154...18H) on the Spitzer
space telescope (Werner et al. 2004ApJS..154....1W 2004ApJS..154....1W) are now publicly
available. These spectra are produced using the bksub.tbl products
from SL and LL modules of final SSC pipeline, version 18.18. From the
IRS data archive, we found a collection of 16986 low-resolution spectra.
The spectra are merged by four slits: SL2 (5.21-7.56 µm), SL1
(7.57-14.28 µm), LL2 (14.29-20.66 µm), and LL1 (20.67-38.00 µm).
As crystalline silicates have no features in the SL2 band, we choose
the spectra that include all the other three bands: SL1, LL2, and LL1
so that the object has a continuous spectrum from about 7.5-38 µm.
In this way, five of the seven infrared complexes of crystalline
silicates are covered, i.e., the 10, 18, 23, 28, and 33 µm complexes.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 89 868 Results of equivalent widths
table4.dat 99 868 Results of significance level and crystallinity
table5.dat 115 868 Results of SIMBAD type
table6.dat 45 55 Summary of SIMBAD Type
table7.dat 123 91 Results of cross-identification with LAMOST
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See also:
V/149 : LAMOST DR2 catalogs (Luo+, 2016)
J/A+A/382/184 : Crystalline silicates around evolved stars (Molster+, 2002)
J/MNRAS/414/500 : Spitzer/IRS ATLAS project source (Hernan-Caballero+, 2011)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- AorkeyID [3543296/33294592] Observation request ID
10- 39 A30 --- Name Object name
41- 49 F9.5 deg RAdeg [3.12686/350.603] Right Ascension in decimal
degrees (J2000)
51- 59 F9.5 deg DEdeg [-81.30813/77.61622] Declination in decimal
degrees (J2000)
61- 65 F5.2 um EW-10 [-1.26/2.07] Equivalent width of 10µm feature
67- 71 F5.2 um EW-18 [-1.65/10] Equivalent width of 18µm feature
73- 77 F5.2 um EW-23 [-0.61/3.78] Equivalent width of 23µm feature
79- 83 F5.2 um EW-28 [-1.32/9.83] Equivalent width of 28µm feature
85- 89 F5.2 um EW-33 [-1.07/5.78] Equivalent width of 33µm feature
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- AorkeyID [3543296/33294592] Observation request ID
10- 39 A30 --- Name Object name
41- 49 F9.5 deg RAdeg [3.12686/350.603] Right Ascension in decimal
degrees (J2000)
51- 59 F9.5 deg DEdeg [-81.30813/77.61622] Declination in decimal
degrees (J2000)
61- 65 F5.2 --- S/U-10 [-2.54/4.01] Significance level of 10µm
feature (1)
67- 71 F5.2 --- S/U-18 [-0.92/2.02] Significance level of 18µm
feature (1)
73- 77 F5.2 --- S/U-23 [-1.02/2.46] Significance level of 23µm
feature (1)
79- 83 F5.2 --- S/U-28 [-1.53/2.09] Significance level of 28µm
feature (1)
85- 89 F5.2 --- S/U-33 [-1.43/1.34] Significance level of 33µm
feature (1)
91- 94 F4.1 % Crystal [17.7/99.7] Crystallinity
96- 99 F4.1 % b_Crystal [2.4/37.4] Lower limit of the crystallinity
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Note (1): The significance level of the crystalline silicate is calculated in
each band as: S/U=Fcrys/σcrys, where Fcrys is crystalline
silicate flux and σcrys is the uncertainty in the measured
flux.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- AorkeyID [3543296/33294592] Observation request ID
10- 39 A30 --- Name Object name
41- 49 F9.5 deg RAdeg [3.12686/350.603] Right Ascension in decimal
degrees (J2000)
51- 59 F9.5 deg DEdeg [-81.30813/77.61622] Declination in decimal
degrees (J2000)
61-101 A41 --- Type Object type from SIMBAD
103-115 A13 --- SpType SIMBAD MK spectral type
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 41 A41 --- Type Object type from SIMBAD
43- 45 I3 --- Num [1/132] Number of source(s) with corresponding
SIMBAD type
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- AorkeyID [3544832/26935552] Observation request ID
10- 38 A29 --- Name Object name
40- 48 F9.5 deg RAdeg [45.58757/346.76211] Right Ascension in decimal
degrees (J2000)
50- 57 F8.5 deg DEdeg [-6.82126/58.66712] Declination in decimal
degrees (J2000)
59- 62 A4 --- Class [STAR QSO] LAMOST class
64- 67 A4 --- Subclass LAMOST subclass
69- 77 E9.2 --- z [-0.00414/0.0422] Redshift of object
79- 80 I2 --- Halpha [-1/1]? Hα line (1)
82-111 A30 --- Type Object type from SIMBAD
113-123 A11 --- SpType SIMBAD MK spectral type
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Note (1): In the column of Hα, 1, 0 and -1 mean the object has a strong
Hα emission line, not strong Hα line and a strong
Hα absorption line, respectively.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 06-Apr-2018