Alfonso Trejo* and Luis F. Rodríguez**
Centro de Radiostronomía y Astrofísica, Universidad Nacional Autónoma de México, Apdo. Postal 3–72, (Xangari), 58089 Morelia, Michoacán, México (* a.trejo@crya.unam.mx, ** l.rodriguez@crya.unam.mx).
Received 2010 January 12
Accepted 2010 July 26
RESUMEN
]]> Reportamos observaciones hechas con el VLA de la línea de 21 cm del HI hacia dos fuentes compactas que podrían estar asociadas con fuentes galácticas extendidas. En el caso de la nebulosa planetaria PHR 1735–333 observamos HI en absorción hacia una fuente de radio no térmica recientemente descubierta en la región, la cual se propuso estaba físicamente asociada con la nebulosa planetaria. Sin embargo, el análisis del espectro de HI en absorción sugiere una distancia mayor para esta fuente no térmica. En el caso del candidato a remanente de supernova SNR G3.8+0.3 obtuvimos espectros de HI en absorción hacia ella y hacia la fuente compacta de radio localizada en su centro. Concluimos que SNR G3.8+0.3 es más distante que la fuente compacta y que por lo tanto no están asociadas físicamente.
ABSTRACT
We report VLA radio observations of the 21 cm HI line toward two compact radio sources that could be associated with extended Galactic sources. In the case of the planetary nebula PHR 1735–333 we observed HI absorption against a non–thermal radio source recently discovered in the region, which was proposed to be physically associated with the planetary nebula. However, from the analysis of the HI absorption spectrum, we suggest a larger distance for this non–thermal source. In the case of the supernova remnant candidate SNR G3.8+0.3 we obtained HI absorption spectra towards it and towards a compact radio source located at its center. We conclude that SNR G3.8+0.3 is more distant than the compact radio source and that they are not physically associated.
Key Words: ISM: individual (SNR G3.8+0.3) — ISM: supernova remnants — planetary nebulae: individual (PHR 1735–333) — radio lines: ISM.
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ACKNOWLEDGMENTS
We thank the referee for many suggestions and for pointing out that the source GPSR 3.826+0.386 is a bright Hα source. AT is supported by a Conacyt scholarship. LFR acknowledges the support of DGAPA, Universidad Nacional Autónoma de México, and of Conacyt (Mexico). This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France.
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