J/A+A/617/A77 Orion Bar Herschel/PACS CO maps (Parikka+, 2018)
High-J CO emission spatial distribution and excitation in the Orion Bar.
Parikka A., Habart E., Bernard-Salas J., Koehler M., Abergel A.
<Astron. Astrophys. 617, A77 (2018)>
=2018A&A...617A..77P 2018A&A...617A..77P (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds; Interstellar medium; Carbon monoxide
Keywords: ISM: individual objects: Orion Bar - ISM: lines and bands -
photon-dominated region
Abstract:
With Herschel, we can for the first time observe a wealth of high-J CO
lines in the interstellar medium with a high angular resolution. These
lines are specifically useful for tracing the warm and dense gas and
are therefore very appropriate for a study of strongly irradiated
dense photodissocation regions (PDRs).
We characterize the morphology of CO J=19-18 emission and study the
high-J CO excitation in a highly UV-irradiated prototypical PDR, the
Orion Bar.
We used fully sampled maps of CO J=19-18 emission with the
Photoconductor Array Camera and Spectrometer (PACS) on board the
Herschel Space Observatory over an area of ∼110"x110" with an angular
resolution of 9". We studied the morphology of this high-J CO line in
the Orion Bar and in the region in front and behind the Bar, and
compared it with lower-J lines of CO from J=5-4 to J=13-12 and 13CO
from J=5-4 to J=11-10 emission observed with the Herschel Spectral and
Photometric Imaging Receiver (SPIRE). In addition, we compared the
high-J CO to polycyclic aromatic hydrocarbon (PAH) emission and
vibrationally excited H2. We used the CO and 13CO observations and
the RADEX model to derive the physical conditions in the warm
molecular gas layers.
Description:
We observed the CO J=19-18 line (137um) in the Orion Bar with the
Herschel/PACS instrument. The observations were carried out on
September 15, 2012, and the total duration was 2687s. A 4x4 raster map
was observed for a total area of ∼110"x110" with full Nyquist
sampling. Each footprint in the raster map is composed of 5x5 spatial
pixels.
Objects:
-----------------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------------
05 35 22.30 -05 24 33.0 Orion Bar = NAME Ori Bar
-----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 121 26 List of fits maps
fits/* . 26 Individual fits maps
--------------------------------------------------------------------------------
See also:
J/ApJ/838/152 : Deep NIR spectrum of the Orion Bar PDR (Kaplan+, 2017)
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26- 48 A23 "datime" Obs.date Observation date (YYYY/MM/DDThh:mm:ss.sss)
50- 51 I2 Kibyte size Size of FITS file
53- 84 A32 --- FileName Name of FITS file in subdirectory fits
86-121 A36 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Anna Parikka, parikka(at)ph1.uni-koeln.de
(End) Patricia Vannier [CDS] 19-Sep-2018