We have undertaken a comprehensive search for 5 cm OH masers in regions visible from Effelsberg with the 100-m telescope (i.e., those with declinations above -29^o^). Our sample is based on bright sources taken from the IRAS Point Source Catalog and/or from previous 18cm OH and H_ 2_O surveys. Among the 165 sources observed, 16 are new (15 exhibit emission and one source shows both absorption and emission). Two new absorption line sources have been tentatively detected. The general properties of the 5cm OH sources are presented and discussed. The 6035MHz line is more often detected than the 6031MHz line. Nevertheless, the latter line is frequently present, a fact that is not explained by present OH excitation models. Simple calculations tend to show that there are enough FIR photons to pump the 6035 and 6031MHz masers, and we found that the statistics of the ratio S_ radio_/S_ IR_ at 18, 5 and 6cm suggest that the maser pumping efficiency decreases with increasing OH excitation. Variability on short (months) or long (years) time-scales is a common feature in many 5 cm OH sources. We also present observations of the 6 GHz satellite lines and report, besides W3(OH), on two certain and perhaps two newly detected weak sources. Some implications on the excitation of OH are briefly discussed.
Class I methanol masers (cIMMs) and 1720MHz OH masers are believed to arise from a common collisional pumping mechanism, and both trace shocked gas regions in supernova remnants (SNRs). However, their coexistence in star formation regions (SFRs) and their association with a front of bipolar outflow (a source of shock-stimulated collisional pumping) remain unclear. To search for collisionally pumped OH(1720) masers, we conducted a Very Large Array survey of the 18cm OH masers and continuum emission toward a sample of 80 SFRs associated with 44GHz cIMMs. Main-line OH maser emission was detected in 50% of the sample, and OH(1720) maser emission was detected in 20%. Continuum emission was detected in 28% of sources. A catalog of the detected OH masers is presented. Individual OH masers are found in close proximity, and the regions of masers of different transitions are often overlapping. A typical linear projected offset between the OH(1720) and OH(1665) masers is ~0.04pc. A remarkable number of ~81% of the OH(1720) masers are associated with the continuum emission. The median separation between the targeted 44GHz cIMMs and OH(1720) masers is ~0.2pc, which is similar to reported distances between cIMMs and HII regions. The observed properties of the detected OH(1720) masers are different from those in SNRs and indicate that a nonlocal line overlap mechanism is responsible for their excitation. Thus, while both 44GHz cIMMs and OH(1720) masers trace shocked gas in SNRs, physical conditions favorable for excitation of cIMMs, but not OH(1720) masers, are present in SFRs.
The NORTH6CM database is a catalog of 53,522 4.85-GHz sources generated by Becker, R. H., White, R. L., Edwards, A. L. 1991, ApJS 75, 1. It covers between 0 degrees and 75 degrees declination using observations taken with the NRAO Greenbank 300-ft telescope by Condon, Broderick and Seielstad (1989). The flux limit of the catalog is dependent on declination and ranges from approximately 40 mJy at 0 degrees to 20 mJy at 60 degrees. The source positions given in the catalog have a 95% confidence radius of approximately 50 arcsec. Spectral indices have been calculated for 29,051 sources which have counterparts in the Texas 365-MHz Northern Sky Survey. This is a service provided by NASA HEASARC .
The 1.4-GHz Northern Sky Catalog - Version: 4 December 1991 This is the 20-cm Northern Sky Catalog of White, R. L. and Becker, R. H. (1992, Ap.J.Supp., in press) containing 30,239 sources detected from the Condon Greenbank images taken at 1.4 GHz over the declination range of -5 degrees to 82 degrees with a flux density limit of 100 mJy. This 20 cm catalog also contains the results of a cross-correlation with catalogs at 6 and 80 cm covering the northern sky between Dec=0 degrees and 70 degrees to give the spectral indices at three frequencies for about 20,000 sources. This is a service provided by NASA HEASARC .
The 21 cm Galactic Plane survey was carried out with the Effelsberg 100-m radio telescope (HPBW = 9.4'). It contains sources from l=357{deg} to l=95.5{deg} and from -4{deg}<b<4{deg}. The data were absolutely calibrated by using the Stockert Northern Sky survey at the same wavelength. Included are 884 compact objects with peak flux densities greater than 98 mJy (or 200 mK Tb) and apparent sizes less than 16'. This survey is especially useful for studying extended emission complexes in the Galactic plane and complements the Effelsberg 11 cm survey of the Galactic plane (Reich et al., Cat. <J/A+AS/85/805>)
We analysed the 21cm Galactic Plane survey carried out with the Effelsberg 100-m telescope for small diameter sources. We present a list of 1830 radio sources with a maximum apparent size of 16' and peak flux densities >160mK or >79mJy/beam area, and a list of 884 radio sources with a maximum apparent size of 16' and peak flux densities >200mK or >98mJy/beam area.
We analysed the 11cm Galactic Plane survey carried out with the Effelsberg 100-m telescope for small diameter sources. We present a list of 6483 radio sources with a maximum apparent size of 12' and peak flux densities >40mJy/beam area. Point-like sources are almost evenly distributed over the surveyed area, except that we miss some sources in the highly confused inner part of the Galaxy and the Cygnus X complex. At Galactic longitudes l>100deg the list of compact sources is almost complete above an integrated flux density limit of 70mJy. Most of them are extragalactic. Extended sources show a concentration towards the Galactic Plane. At longitudes l<100deg the scale height is about 0.6deg. An excess of about 900 extended sources is most likely of Galactic structure.
We report and discuss the results of a 22-cm radio survey carried out with the Australia Telescope Compact Array (ATCA) covering the A3528 complex, a chain formed by the merging ACO clusters A3528-A3530-A3532, located in the central region of the Shapley Concentration. Simultaneous 13-cm observations are also presented. Our final catalogue includes a total of 106 radio sources above the flux density limit of 0.8mJy. By cross-correlation with optical and spectroscopic catalogues we found 32 optical counterparts, nine of them belonging to the A3528 complex.
A compilation of H I line fluxes, systemic velocities and linewidths is presented for 840 detected galaxies, mostly in the vicinities of 30 nearby rich clusters out to a redshift of z~0.04, specifically for use in applications of the Tully-Fisher distance method. New 21 cm H I line profiles have been obtained for ~500 galaxies in 27 Abell clusters visible from Arecibo. Upper limits are also presented for 246 galaxies for which H I emission was not detected. In order to provide a homogeneous linewidth determination optimized for Tully-Fisher studies, these new data are supplemented by the reanalysis of previously published spectra obtained both at Arecibo and Green Bank that are available in a digital archive. Corrections for instrumental broadening, smoothing, signal-to-noise and profile shape are applied, and an estimate of the error on the width is given. When corrected for turbulent broadening and viewing angle, the corrected velocity widths presented here will provide the appropriate line width parameter needed to derive distances via the Tully-Fisher relation.
The 11 cm radio continuum radiation of the Galactic Plane is shown in the form of an atlas of contour maps covering the range l=357.4 to 76{deg}, |b|=1.5{deg} or less. The angular resolution is about 4.3arcmin and the sensitivity is 50mK T_B_ (or 20mJy/beam area). Additionally a catalog of 1212 small diameter radio sources has been compiled.
