J/ApJS/149/365 Bright filamentary structures in the ISM (Jackson+, 2003)
A catalog of bright filamentary structures in the interstellar medium.
Jackson T., Werner M., Gautier Iii T.N.
<Astrophys. J. Suppl. Ser., 149, 365-373 (2003)>
=2003ApJS..149..365J 2003ApJS..149..365J
ADC_Keywords: Interstellar medium ; Infrared sources
Keywords: catalogs - infrared: ISM - ISM: structure - methods: data analysis -
techniques: image processing
Abstract:
We present a listing of prominent filamentary structures in the
interstellar cirrus, selected with an eye toward current and planned
far-infrared and submillimeter polarimetry facilities. The filaments
were identified on the 100µm plates of the IRAS Sky Survey Atlas
(ISSA, Wheelock et al. 1994, IRAS Sky Survey Atlas: Explanatory
Supplement (JPL Publ. 94-11; Pasadena: JPL)), using a computer vision
algorithm that is unbiased with respect to source intensity. Our
catalog is two-tiered: the selection criteria in the Galactic plane
are based on the sensitivity limits of airborne polarimeters such as
the proposed HALE instrument for SOFIA, and away from the plane the
limits are dictated by the sensitivities of balloon-borne cosmic
microwave background experiments, such as BOOMERanG and MAXIMA.
Infrared detector technology is currently at the point where detecting
the polarization of the interstellar cirrus is feasible, and we hope
this catalog will assist any experimenter undertaking this task.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 95 83 List of Filaments Satisfying our Criteria for
|b|>20°
table2.dat 95 48 List of Filaments Satisfying our Criteria for
|b|<20°
table3.dat 95 10 List of Filaments Satisfying our Criteria for
the Large Magellanic Cloud
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Byte-by-byte Description of file: table?.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [JWG2003] Sequential number
5- 7 I3 --- Plate ISSA plate number on which the filament was
detected
9- 14 F6.2 arcmin Length Arc length
16- 20 F5.1 MJy/sr F100um Averaged flux at 100µm (1)
22- 25 F4.1 mK DT340 Average flux expressed as a temperature (1)
27- 28 I2 h RAe1h Endpoint 1 right ascension (B1950)
30- 33 F4.1 min RAe1m Endpoint 1 right ascension (B1950)
35 A1 --- DEe1- Endpoint 1 declination sign (B1950)
36- 37 I2 deg DEe1d Endpoint 1 declination (B1950)
39- 40 I2 arcmin DEe1m Endpoint 1 declination (B1950)
42- 43 I2 h RAh Midpoint right ascension (B1950)
45- 48 F4.1 min RAm Midpoint right ascension (B1950)
50 A1 --- DE- Midpoint declination sign (B1950)
51- 52 I2 deg DEd Midpoint declination (B1950)
54- 55 I2 arcmin DEm Midpoint declination (B1950)
57- 62 F6.2 deg GLON Midpoint galactic longitude
64- 69 F6.2 deg GLAT Midpoint galactic latitude
71- 72 I2 h RAe2h Endpoint 2 right ascension (B1950)
74- 77 F4.1 min RAe2m Endpoint 2 right ascension (B1950)
79 A1 --- DEe2- Endpoint 2 declination sign (B1950)
80- 81 I2 deg DEe2d Endpoint 2 declination (B1950)
83- 84 I2 arcmin DEe2m Endpoint 2 declination (B1950)
86- 89 F4.2 --- Cur Curvature measure (2)
91- 95 F5.1 deg-2 Cont Contrast measure (3)
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Note (1): Averaged flux (computed as sum of pixel brightnesses/number of pixels
belonging to object) at 100µm from the data presented in Schlegel
et al. (1998ApJ...500..525S 1998ApJ...500..525S) and extrapolated to 340GHz and expressed
as a temperature based on the routines in Finkbeiner et al.
(1999ApJ...524..867F 1999ApJ...524..867F).
Note (2): The curvature measure is simply defined as the ratio of the
endpoint-to-endpoint distance to the arc length of the filament and
hence ranges from 0 to 1, with the straightest features having the
higher ratio.
Note (3): The contrast measure is defined as Ipp/I, where the quantity
Ipp (2nd derivative in the direction perpendicular to the
filament axis) measures this curvature.
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 19-Dec-2003