First List of IRAS Sources

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Infrared astronomy Wavelengths(/lm) Detector size Preliminary Centre Bandwidth on sky (arc NEFD* min) 2 {Jy) First list of IRAS sources 12 6 0.8x4.5 0.07 25 II 0.8 x 4.6 0.065 from the IRAS working group 60 40 J.5X4.7 0.085 100 37 3.0x5.0 0.30 THE Infrared Astronomical Satellite The most important are: (1) the objects are *I sigma for a single pass. (IRAS) was launched on 26 January 1983 strong emitters of far-IR radiation; (2) and is operating beautifully. It is expected non-IRAS observations are critical for pro A second instrument is a low-resolution to have a lifetime of as long as eleven per interpretation; (3) the objects are spectrometer which will operate between 6 months. It spends about 60 per cent of the typical or interesting representatives of cer and 241-Lm with a resolving power between time performing a survey of the entire in tain classes of astronomical objects. 10 at the shortest wavelengths and 35 at the frared (IR) sky. The instruments in the focal plane have longest. The spectrometer will normally The IRAS team plans to publish a com been described elsewhere (J. Br. in• measure objects brighter than 50 times the plete catalogue of the sky survey within one terplanet. Soc. 36, no. 1; Nature 303, 287; noise in the survey instrument. year of the end of the mission. Meanwhile, 1983). Most observations made by the The third instrument, the chopped it will publish circulars about every two to survey instrument are in four broad photometric channel (CPC), produces three weeks and the first is presented here. wavelength bands whose parameters are small maps of selected objects in two bands Each circular will contain from 10 to 50 given in the table in the next at about 50 and 100 1-1m. The instrument sources selected for a variety of reasons. column. has a circular diaphragm of 1.2 arc min diameter and the maps are normally 3 x 3 Source name Coordinates Flux densities (Jy) at Remarks or 9 x 9 arc min. When the CPC operates, IRAS RA/ dec 12 J.Am 25 J.Am 60 !Am 100 I'm data from the survey instrument are not 0344 + 327POI 03h 44m 32s 1.6 5.2 18 22 Dark cloud; B5 + 32° 42.5' close to CO peak recorded. 0401 +261POI 04h Olm 40s 3.3 16 54 75 Dark cloud; between The normal survey measurements are +26° 10.8' Lynds 1491 & 8207 repeated on time scales of seconds, hours 0406 + 085 PO I 04h 06m 30s <0.3 0.4 3.7 9.2 Gal; NGC 1517/ and days. CPC observations are repeated +08° 31.!' UGC 2970/ at least once and more than several hours ZWG418.013 apart; by such repetitions asteroids and 0409 + 054PO I 04h 09m 42s 0.56 0.80 9.4 20 Gal; UGC 2983/ other rapidly moving objects can be +05° 25.2' MCG + 01-11-013/ distinguished. ZWG418.014 A preliminary absolute photometric 0415 +014POI 04h 15m 05s <0.2 <0.4 3.1 6.7 Gal? Between +01° 26.!' MGC+00-11-046& calibration, probably correct to within 20 MCG + 00-11-047 per cent, has been made based on a Tauri {II ZW 007/ and the asteroid Fortuna. Flux densities are ZWG 392 .017) given in Janskys for the central wavelengths 0419+039POI 04h 19m ISs <0.3 0.3 2.1 5.5 Gal; IC 2057 I listed above and for an energy distribution +03° 55.8' ZWG419.002 which is flat in the flux per logarithmic fre 0426 + 647POI 04h 26m 02s 1.0 8.0 50 57 Gal; NGC 1569 quency interval. For other energy distribu +64° 44.4' tions, the flux density at the central 0432-143POI 04h 32m 33s 1.1 2.8 7.9 10 Dark cloud; Lynds -14° 19.2' 1642/ Gal; wavelength will be related to that listed by: MCG-02-12-042? f (true)=f (flat)/ K (true spectrum). Here K 0459-341POI 04h 59m 50s <0.2 0.4 2.9 5.3 Compact group of (true spectrum) is given by: -34° 06.1' 3 gals; Klem 09/ MCG-06-12-03 Source spectrum 121'm 2SI'm 6011m IOOI'm 0505-375POI 05h 05m 59s 3.7 16 110 170 Gal; NGC 1808 4800 K black body 1.40 1.32 1.32 1.12 Flat in wavelength -37° 34.5' 0.95 0.95 0.99 0.99 Flat in flu x/octave 1.000 1.000 1.000 1.000 0520-115POI 05h 20m 13s <0.3 0.2 4.0 12 lnreracting gals; Flat in frequency 1.09 1.07 1.05 1.02 0 -II 32.7' NGC 1888/ 1889 100 K black body 1.15 0.88 1.03 1.06 1409-651POI 14h 09m 19s 19 65 280 340 Gal; Al409-65/ -65° 06.7' Circinus gal 1636-487POI 16h 36m 16s 180 3.5K >ISK >23K Open cluster/ flu The flux densities are derived assuming -48° 65.7' region/Wolf the sources to be point-like. Hence, if a Rayet (point-like) source is extended, its integrated flux den NGC6193/ sity will be greater than that quoted. The RCW 108/ precision of the flux densities is shown by the WRAY 19.47 number of significant figures quoted. 1648-591POI 16h 48m 26s 1.5 5.5 43 84 Gal; NGC 6221 -59° 08.0' The positional uncertainties are less than 1710-370POI 17h !Om 21s 32 350 890 580 Planetary nebula; I arc min in either coordinate and can be as -37° 02.7' NGC6302 small as 10 arc s. Refined estimates of the 1755-213POI 17h 55m 05s 5.0 24 33 9.3 OH/ IR star; uncertainties will be given in future reports. -21° 20.8' OH 8.5 + 1.4 The circulars are the responsibility of the 1827-145POI 18h 27m 40s 22 140 130 37 OH/IR star; joint IRAS science working group of which -14° 31.2' OH 17.7-2.0 H. Habing and G. Neugebauer are the co A410POI 16h 37m 44s 12 27 12 6.0 Asteroid; 410 chairmen. S. Pottasch (Kapteyn -13° 38. )' LIT Chloris 83 Feb 10.3 Astronomical lnstitue, PO Box 800, 7900 A V Groningen, The Netherlands) will be The source name consists of four parts: {I) 'IRAS' indicates the origin; (2) right ascension {RA) in the editor-in-charge and N. Boggess and P. hours and minutes; (3) declination (dec) in decimal degrees, multiplied by !Oand then truncated (e.g. Hacking (IRAS Project, Jet Propulsion + 32° 42' 21" = > + 327); (4)an appendix starting with P and followed by the number of the circular; Laboratory, Pasadena, California 91109) this appendix stresses that the data are preliminary. Position is given at Equinox 1950.0. The will coordinate the production of the cir measurements have been made between epochs 1983.1 and 1983.3. culars on the US side. LJ