J/ApJ/878/151 DIB Measurements in 25 atlas sightlines (Fan+, 2019)
The Apache Point Observatory Catalog of Optical Diffuse Interstellar Bands.
Fan H., Hobbs L.M., Dahlstrom J.A., Welty D.E., York D.G., Rachford B.,
Snow T.P., Sonnentrucker P., Baskes N., Zhao G.
<Astrophys. J., 878, 151 (2019)>
=2019ApJ...878..151F 2019ApJ...878..151F (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Stars, OB ; Extinction ; Interstellar medium
Keywords: dust, extinction - ISM: lines and bands - ISM: molecules
Abstract:
Aiming for a new and more comprehensive DIB catalog between 4000 and
9000Å, we revisited the Atlas Catalog based on the observations of
HD 183143 and HD 204827. Twenty-five medium to highly reddened sight
lines were selected, sampling a variety of spectral types of the
background star and the interstellar environments. The median
signal-to-noise ratio (S/N) of these spectra is ∼1300 around 6400Å.
Compared to the Atlas Catalog, 22 new DIBs were found, and the
boundaries of 27 (sets of) DIBs were adjusted, resulting in an updated
catalog containing 559 DIBs that we refer to as the Apache Point
Observatory Catalog of Optical Diffuse Interstellar Bands.
Measurements were then made based on this catalog. We found our survey
most sensitive between 5500 and 7000Å, due largely to the local S/N
of the spectra, the relative absence of interfering stellar lines, and
the weakness of telluric residuals. For our data sample, the number of
DIBs detected in a given sight line is mostly dependent on EB-V and
less on the spectral type of the background star. Some dependence on
the molecular fraction fH2 is observed, but it is less well
determined owing to the limited size of the data sample. The
variations of the wavelengths of each DIB in different sight lines are
generally larger than those of the known interstellar lines CH+, CH,
and KI. Those variations could be due to the inherent error in the
measurement, or to differences in the velocity components among sight
lines.
Description:
The tables contain measurements of the 559 DIBs listed in the Apache
Point Observatory Catalog of Diffuse Interstellar Bands, as part of
the ongoing DIB survey project at APO and the University of Chicago.
All spectra used for measurements were obtained with the 3.5m
telescope at APO and its ARC echelle spectrograph (ARCES). These
spectra have R∼38000, corresponding to a velocity resolution of 8km/s.
The measurements were made with arcexam, a software specialized for
the DIB measurement and coded by D. Welty. Please refer to Fan et al.
(2019ApJ..878...151F 2019ApJ..878...151F) for more detailed descriptions on these
measurements. Users of these data are kindly asked to cite this work,
as well as Hobbs et al. (2008ApJ..680...1256H, 2009ApJ..705...32H.
Cat. J/ApJ/705/328) in their related publications.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 195 25 Information on the 25 sight lines selected
for this work
cernis52.dat 60 557 DIB measurements for the sightline of Cernis-52
cygob25.dat 60 557 DIB measurements for the sightline of CygOB2-5
cygob212.dat 60 557 DIB measurements for the sightline of CygOB2-12
hd20041.dat 60 557 DIB measurements for the sightline of HD20041
hd23180.dat 60 557 DIB measurements for the sightline of HD23180
hd23512.dat 60 557 DIB measurements for the sightline of HD23512
hd24534.dat 60 557 DIB measurements for the sightline of HD24534
hd24912.dat 60 557 DIB measurements for the sightline of HD24912
hd28482.dat 60 557 DIB measurements for the sightline of HD28482
hd37061.dat 60 557 DIB measurements for the sightline of HD37061
hd37903.dat 60 557 DIB measurements for the sightline of HD37903
hd43384.dat 60 557 DIB measurements for the sightline of HD43384
hd147889.dat 60 557 DIB measurements for the sightline of HD147889
(corrected version, 03-Aug-2020)
hd147084.dat 60 557 DIB measurements for the sightline of HD147084
hd148579.dat 60 557 DIB measurements for the sightline of HD148579
hd166734.dat 60 557 DIB measurements for the sightline of HD166734
hd168625.dat 60 557 DIB measurements for the sightline of HD168625
hd175156.dat 60 557 DIB measurements for the sightline of HD175156
hd183143.dat 60 557 DIB measurements for the sightline of HD183143
hd190603.dat 60 557 DIB measurements for the sightline of HD190603
hd194279.dat 60 557 DIB measurements for the sightline of HD194279
hd204827.dat 60 557 DIB measurements for the sightline of HD204827
hd206267.dat 60 557 DIB measurements for the sightline of HD206267
hd223385.dat 60 557 DIB measurements for the sightline of HD223385
hd281159.dat 60 557 DIB measurements for the sightline of HD281159
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See also:
J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Star Star name, sorted by R.A. of the program star
13 A1 --- n_Star [f] Note on Star (1)
15- 23 A9 --- OName Other name
25 A1 --- n_OName [gh] Note on OName (1)
27- 39 A13 --- SpType Spectral Type
41- 44 F4.2 mag E(B-V) Color excess
46- 48 I3 km/s vsini ? Rotational velocity
50 A1 --- l_fH2 Limit flag on fH2
51- 54 F4.2 --- fH2 Mass fraction of molecular hydrogen to all
neutral hydrogen along the sight line
55 A1 --- n_fH2 [*] Note on fH2 (2)
57- 60 F4.1 % DPA Number of detected DIBs in each sight line
divided by 559 (3)
61 A1 --- --- [/]
62- 65 F4.1 % DPM Number of detected DIBs divided by the total
measuring attempts made in each sight line,
which is 559 minus the number of rejections
due to various reasons
67- 78 A12 --- FileName Name of the file with DIBs
80- 85 I6 --- HDcomp HD number of comparison star
87- 95 A9 --- SpTypecomp Spectral Type of comparison star
97-100 F4.2 mag E(B-V)comp Color excess of comparison star
102 A1 --- l_vsinicomp Limit flag on vsinicomp
103-105 I3 km/s vsinicomp Rotational velocity of comparison star
107-195 A89 --- Com Comments
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Note (1): Notes as follows:
f = Spectroscopic binaries identified in our observations and/or Binary star
DataBase (BDB; Kovaleva et al., 2015A&C....11..119K 2015A&C....11..119K)
g = Often referred to as Cyg OB2 5
h = Often referred to as Cyg OB2 12
Note (2): *: it was computed by using N(CH) as a surrogate for N(H_2) and/or
W(5780) for N(H). See Fan et al. (2017, Cat. J/ApJ/850/194) for details.
Note (3): The number of DIBs reported in individual star files.
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Byte-by-byte Description of file: [ch]*.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- idx [1/559] Index number (1)
5- 11 F7.2 0.1nm cWav Average wavelength as in the APO catalog
13- 19 F7.2 km/s cFWHM Average FWHM as in the APO catalog
21- 26 F6.2 km/s cXm2 Average Xm2 factor as in the APO catalog (2)
28- 34 F7.2 0.1nm mWav ? Measured wavelength
36- 40 F5.2 0.1nm mFWHM ? Measured FWHM
42- 47 F6.1 10-13m mEW ? Measured equivalent width
49- 52 F4.1 10-13m e_mEW ? 1-sigma uncertainty of EW (3)
54- 58 F5.2 0.1nm mXm2 ? Measured xm2 factor (2)
60 A1 --- D [cdrl] Marker for detection (4)
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Note (1): Two broad DIBs were reported in Sonnentrucker et al.
(2018ApJS..237...40S 2018ApJS..237...40S) at 4761/4764 and 4964 Angstrom, and were included in the
APO Catalog with indexes of No. 16 and 28. However, we were not able to
measure these broad DIB in our high-resolution spectra, and they were not
included in the data tables. As a result, the data tables have 557 rows of
data, rather than 559 rows as in the APO Catalog of DIB.
Note (2): The xm2 factor is the apparent optical depth weighted second moment of
the DIB profile and is related to its width. See paper for definition and
calculation.
Note (3): Due to the limited space of the table, any uncertainty that is greater
than 100 milli-Angstrom has been convert to 99.9 as a default value.
Note (4): The measurement of a DIB depends on factors such as its strength, the
SNR, and whether there are contaminations from stellar or telluric lines in
the region. Thus the outcome is more complicated than simply "detection" or
"upper-limits".
Four conditions are considered here, as given in the "D" columns, as follows:
r = Rejection. The DIB could not be measured due to severe contamination,
e.g. on top of a stellar line and could not be discerned. No attempt of
measurement was made and no data would be provided, such as the
measurement of DIB 4259.00 in HD20041.
l = Upper limit. The DIB was measured but not detected at 3-sigma level. For a
such measurement, information available was the upper limit of the EW,
which was three times the uncertainties. Refer to the measurement of DIB
4363.83 in HD20041 as an example of such cases.
d = Detection. The DIB was measured and detected at 3-sigma level, and no
interfering with stellar lines, telluric residuals, or any other sources
of contaminations has been identified. Detailed information regarding its
measured wavelength, FWHM, EW, 1-sigma uncertainty, and the xm2 factor,
were provided. Such measurements, e.g. the measurement of DIB 4371.39 in
HD20041, are the most reliable data for any quantitative analysis.
c = Detection with contamination. Some interference from contaminating sources
has been identified, but its effect was deemed minor, such as when a DIB
lay adjacent to a stellar line but the peaks could be well-resolved, or
when the center part of the DIB was well-identified between two telluric
residuals which made its integration boundaries less clear.
Like the "Detection" cases, detailed information regarding the
measurement were provided, such as the DIB 4779.85 measurement of
HD20041. These contaminated measurements should be excluded from analysis
pursuing the highest standard of accuracy.
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Acknowledgements:
Haoyu Fan, hfan58(at)uwo.ca ,
NAOC/University of Chicago/Western Univiversity
Donald G. York, don(at)astro.uchicago.edu
History:
28-Apr-2020: on-line version
03-Aug-2020: corrected version of hd147889.dat table (from author)
10-Aug-2022: BD +40 4220 removed in Table 1 for VI Cyg 12 (it is VI Cyg 5);
acknowledgments to Daniel Majaess.
(End) Haoyu Fan [NAOC, Univ. of Chicago], Patricia Vannier [CDS] 28-Apr-2020