J/ApJ/852/102 Herschel nearby isolated low-mass clouds maps (Sadavoy+, 2018)
Intensity-corrected Herschel observations of nearby isolated low-mass clouds.
Sadavoy S.I., Keto E., Bourke T.L., Dunham M.M., Myers P.C., Stephens I.W.,
Di Francesco J., Webb K., Stutz A.M., Launhardt R., Tobin J.J.
<Astrophys. J., 852, 102-102 (2018)>
=2018ApJ...852..102S 2018ApJ...852..102S (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Spectra, millimetric/submm
Keywords: dust, extinction - ISM: clouds - ISM: structure - stars: formation -
submillimeter: ISM
Abstract:
We present intensity-corrected Herschel maps at 100, 160, 250, 350,
and 500µm for 56 isolated low-mass clouds. We determine the
zero-point corrections for Herschel Photodetector Array Camera and
Spectrometer (PACS) and Spectral Photometric Imaging Receiver (SPIRE)
maps from the Herschel Science Archive (HSA) using Planck data. Since
these HSA maps are small, we cannot correct them using typical
methods. Here we introduce a technique to measure the zero-point
corrections for small Herschel maps. We use radial profiles to
identify offsets between the observed HSA intensities and the expected
intensities from Planck. Most clouds have reliable offset measurements
with this technique. In addition, we find that roughly half of the
clouds have underestimated HSA-SPIRE intensities in their outer
envelopes relative to Planck, even though the HSA-SPIRE maps were
previously zero-point corrected. Using our technique, we produce
corrected Herschel intensity maps for all 56 clouds and determine
their line-of-sight average dust temperatures and optical depths from
modified blackbody fits. The clouds have typical temperatures of
∼14-20K and optical depths of ∼10-5-10-3. Across the whole sample,
we find an anticorrelation between temperature and optical depth. We
also find lower temperatures than what was measured in previous
Herschel studies, which subtracted out a background level from their
intensity maps to circumvent the zero-point correction. Accurate
Herschel observations of clouds are key to obtaining accurate density
and temperature profiles. To make such future analyses possible,
intensity-corrected maps for all 56 clouds are publicly available in
the electronic version.
Description:
For all the sources listed in table1, maps of dust temperature and
optical depth at 353GHz for all globules as fits files.
For all the sources listed in table1, maps of dust temperature,
optical depth at 353GHz, and corrected Herschel intensities are
available as fits files. The intensity maps contain labels to indicate
the reliability of their intensity corrections with Group A as the
most reliable, Group B as somewhat reliable, and Group C as least
reliable. See paper for details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 93 56 Nearby Globules in the Herschel Archive
refs.dat 173 25 References and method used
fits/* . 504 Individual dust temperature, optical depth
and intensity-corrected maps
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See also:
VI/139 : Herschel Observation Log (Herschel Science Centre, 2013)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Globule name
12 A1 --- n_Name [a] Note on Name (1)
14- 15 I2 h RAh Right ascension (J2000)
17- 18 I2 min RAm Right ascension (J2000)
20- 23 F4.1 s RAs Right ascension (J2000)
25 A1 --- DE- Decliniation sign (J2000)
26- 27 I2 deg DEd Decliniation (J2000)
29- 30 I2 arcmin DEm Decliniation (J2000)
32- 33 I2 arcsec DEs Decliniation (J2000)
35- 48 A14 --- PropID Proposal ID
51- 67 A17 --- Assoc Association
69- 71 I3 pc Dist Distance, or lower value of
interval of distance
72 A1 --- --- [-]
73- 75 I3 pc Dist2 ? Upper value of interval of distance
77- 79 I3 pc e_Dist ? rms uncertainty on Dist
81- 85 A5 --- Ref References, in refs.dat file
87- 93 A7 --- fname Name used in fits files (2)
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Note (1): a: We assume the same distance as CB 175, but we caution that CB 175
and CB 176 have different gas velocities and may not be related. CB 176 has a
velocity of ~=16km/s, whereas CB 175 is at ~=10km/s (Clemens et al.,
1991ApJS...75..877C 1991ApJS...75..877C).
Note (2): Name used in fits files in subdirectory fits:
optical depth maps:
fname_tau.fits, fnametauerror.fits,
dust temperature maps:
fname_temperature.fits, fnametemperatureerror.fits.
intensity-corrected maps:
fnamepacs100intensitycorrectedgradeN.fits,
fnameintensitycorrected_gradeN.fits,
fnamespire250intensitycorrectedgradeN.fits,
fnamespire350intensitycorrectedgradeN.fits,
fnamespire500intensitycorrectedgradeN.fits
where N could be A, B or C
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 44 A21 --- Auth Author's name
46- 66 A21 -- Com Comments
68-173 A106 --- Meth Measurement method used
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History:
From electronic version of the journal
and Sarah Sadavoy, sarah.sadavoy(at)cfa.harvard.edu
(End) Patricia Vannier [CDS] 28-May-2018