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Edgar A. Ramírez

Publications and source records attributed to Edgar A. Ramírez.

2 recordsLinked to original sources

Solvepol: a reduction pipeline for imaging polarimetry data

We present a newly, fully automated, data pipeline: Solvepol, designed to reduce and analyze polarimetric data. It has been optimized for imaging data from the Instituto de Astronomia, Geofisica e Ciencias Atmosfericas (IAG) of the University of Sao Paulo (USP), calcite Savart prism plate-based IAGPOL polarimeter. Solvepol is also the basis of a reduction pipeline for the wide-field optical polarimeter that will execute SOUTH POL, a survey of the polarized Southern sky. Solvepol was written using the interactive data language (IDL) and is based on the image reduction and analysis facility (IRAF) task pccdpack, developed by our polarimetry group. We present and discuss reduced data from standard stars and other fields and compare these results with those obtained in the IRAF environment. Our analysis shows that Solvepol, in addition to being a fully automated pipeline, produces results consistent with those reduced by pccdpack and reported in the literature.

astro-ph.IM↗

The Rare 23.1-GHz Methanol Masers in NGC 7538 IRS 1

We present high angular resolution (FWHM_beam < 0.2") observations of the 23.1-GHz methanol (CH_3OH) transition toward the massive-star forming region NGC 7538 IRS 1. The two velocity components previously reported by Wilson et al. are resolved into distinct spatial features with brightness temperatures (T_B) greater than 10^4 K, proving their maser nature. Thus, NGC 7538 IRS 1 is the third region confirmed to show methanol maser emission at this frequency. The brighter 23.1-GHz spot coincides in position with a rare formaldehyde (H_2CO) maser, and marginally with a 22.2-GHz water (H_2O) maser, for which we report archival observations. The weaker CH_3OH spot coincides with an H_2O maser. The ratio of T_B for the 23.1-GHz masers to that of the well-known 12.2-GHz CH_3OH masers in this region roughly agrees with model predictions. However, the 23.1-GHz spots are offset in position from the CH_3OH masers at other frequencies. This is difficult to interpret in terms of models that assume that all the masers arise from the same clumps, but it may result from turbulent conditions within the gas or rapid variations in the background radiation field.

astro-ph.GA↗