[tel-00726959, v1] Caractériser le milieu interstellaire ... - HAL - INRIA

0.080.09 0.1A&A 541, A58 (2012)0.140.0716˚30'0.11δ (J2000)0.1316˚00'B2251+1580.07 0.09 0.08 0.154peakCO15˚30'16˚20'0.060.0622h54m 22h52m 22h50mα (J2000)5.71T r* [Kelvin]3210NWB2251tel-00726959, version 1 - 31 Aug 2012δ(J2000)16˚10'16˚00'22h55m 22h54mλ=86.5 0.222h53mα (J2000)24B2251+15813e −τ -1CS(2-1)0.412 CO0.2HCO0.0+H I-0.2-0.4-20 -10 0V LSR (KM S -1 )Fig. 7. The sky field around the position of B2251+158 (C454.3), as in Fig. 2. The map of reddening at upper left is offset to show a separatepeak to the Northwest near 22 H 50 M and a profile at the position of this peak is shown at upper right, shaded green and labeled “NW”, along withprofiles toward 3C 454.3 (shaded) and at the peak of the small clump that is seen immediately adjacent to the continuum source.nearly all HCO + absorption components will be found in nearbyemission after a small search. In terms of numbers, in this workwe observed 20 absorption line components (and a few distinctline wings) with 13 carbon monoxide emission counterparts towardthe continuum targets, and we found 23 CO emission componentswithin 15 ′ of the background continuum source duringthe mapping.The following gives some conclusions that are drawn fromthe preceding presentation; they should generally be understoodas applying on a component-by-component basis.From the standpoint of CO emission.1) In every case where CO emission was detected toward thebackground source, much stronger emission was also detectedwithin approximately 15 ′ and often much less.2) Near B0355+508, B0528+134 and B2200+430 the nearbystronger emission was very strong indeed, with peak linetemperatures of 10−12 K and/or line profile integrals as largeas 20 K km s −1 .3) 1) and 2) are also generally true for kinematic componentsthat were present in absorption toward the continuum sourcebut not detected in emission there (7 of 20 components).4) In one case only (B1928+738), representing 1 of 11 fieldsand 1 of 20 kinematic absorption line components, the entirefield mapped was devoid of emission when emission was notdetected toward the continuum source (from a kinematic absorptionline component). The field mapped around B1928was only 20 ′ × 20 ′ as against 30 ′ × 30 ′ or more for all of theother fields.5) In 2 fields we found an emission feature without a counterpartin molecular absorption toward the background continuumobject (B1954 and B0355 at −20 km s −1 ).From the standpoint of absorption.1) The same kinematic components are seen in both absorptionand emission with angular separations of up to 15 ′ .2) The absorption spectra toward a background source are a previewof what will be seen in emission in a larger field aboutthe background source.A58, page 10 of 23