The prime focus CCD camera of the KPNO 4 m telescope has been used to image Andromeda III, a dwarf spheroidal galaxy companion to M31, in the V and I bands. The resulting color-magnitude diagram shows a well defined giant branch whose tip luminosity corresponds to that expected for an old metal-poor population at the distance of M31. By comparing these data with the giant branches of metal-poor population at the distance of M31. By comparing these data with the giant branches of Galactic globular clusters, we determine that the abundance of And III is [Fe/H]=-2.0+/-0.15; with this abundance And III lies on the luminosity-abundance relation defined by the Galactic dwarf spheroidal galaxies. There is some evidence for a small (0.16<{sigma}([Fe/H])<0.24) intrinsic abundance dispersion within And III, but we are unable to unambiguously establish its presence. A study of the And III I-band luminosity function yields a distance modulus (m-M)_0_ of 24.4+/-0.2 for this galaxy, and indicates that the fraction of intermediate-age (3 to 10Gyr) population in And III is approximately 10+/-10 percent. In all these aspects And III, like And I, is similar to the Galactic dwarf spheroidal systems, indicating that M31 and the Galaxy provided similar conditions for the evolution of such galaxies.
The Cambridge Low Frequency Synthesis Telescope has been used at 151 MHz to survey a region of 1393 square degrees, in the range RA 9h to 16h, Dec 20deg to 35deg, with an angular resolution of 108x108cosec(dec) arcsec^2^. The rms noise on the maps is in general ~35-55 mJy/beam but varies considerably and exceeds this in some areas. We have extracted sources with signal-to-noise ratio > 5.5, a total of 5526, and present a catalogue of their positions and flux densities.
The Cambridge Low Frequency Synthesis Telescope has been used at 151MHz to survey three regions centred at RA=10h05min, DE=53{deg}54', RA=10h42min, DE=57{deg}36' and RA=13h32min, DE=38{deg}10', each of area 7.3x7.3cosec(DE)deg^2^. The resolution is 70x70cosec(DE)arcsec^2^, and the rms noise on the maps is typically 15mJy/beam. We present positions and flux densities for 2381 sources which have signal-to-noise ratios >5.5.
Orion KL has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. The main goal is to systematically study spectral characteristics of Orion KL in the 1.3cm band. We carried out a spectral line survey (17.9GHz to 26.2GHz) with the Effelsberg-100m telescope towards Orion KL. We find 261 spectral lines, yielding an average line density of about 32 spectral features per GHz above 3 sigma. The identified lines include 164 radio recombination lines (RRLs) and 97 molecular lines. A total of 23 molecular transitions from species known to exist in Orion KL are detected for the first time in the interstellar medium. Non-metastable ^15^NH_3_ transitions are detected in Orion KL for the first time. Based on the velocity information of detected lines and the ALMA images, the spatial origins of molecular emission are constrained and discussed. A narrow feature is found in SO_2_ (8_1,7_-7_2,6_), possibly suggesting the presence of a maser line. Column densities and fractional abundances relative to H_2_ are estimated for 12 molecules with LTE methods. Rotational diagrams of non-metastable ^14^NH_3_ transitions with J=K+1 to J=K+4 yield different results; metastable ^15^NH_3_ is found to have a higher excitation temperature than non-metastable ^15^NH_3_, indicating that they may trace different regions. Elemental and isotopic abundance ratios are estimated: ^12^C/^13^C=63+/-17, ^14^N/^15^N=100+/-51, D/H=0.0083+/-0.0045. The dispersion of the He/H ratios derived from H_alpha/He_alpha_ pairs to H_delta_/He_delta_ pairs is very small, which is consistent with theoretical predictions that the departure coefficients bn factors for hydrogen and helium are nearly identical. Based on a non-LTE code neglecting excitation by the infrared radiation field and a likelihood analysis, we find that the denser regions have lower kinetic temperature, which favors an external heating of the Hot Core.
We present results from deep radio observations taken with the Very Large Array at a center frequency of 1400MHz covering a region of the Spitzer Wide-area InfraRed Extragalactic Survey of the Spitzer Legacy survey, centered at 10:46:00, +59:01:00 (J2000). The reduction and cataloging of radio sources are described. An electronic catalog of the sources detected above 5{sigma} is also presented. The survey presented is the deepest so far in terms of the radio source density on the sky. Perhaps surprisingly, the sources down to the bottom of the catalog appear to have median angular sizes still greater than 1-arcsec, like their cousins 10-100 times stronger. The shape of the differential logN-logS counts also seems to require a correction for the finite sizes of the sources to be self-consistent. If the logN-logS normalization remains constant at the lowest flux densities, there are about six sources per square arcminute at 15uJy at 20cm. Given the finite-source size this implies that we may reach the natural confusion limit near 1uJy.
This paper presents 452 new 21-cm neutral hydrogen line measurements carried out with the FORT receiver of the meridian transit Nancay radiotelescope (NRT) in the period April 2003-March 2005. This observational programme is part of a larger project aiming at collecting an exhaustive and magnitude-complete HI extragalactic catalogue for Tully-Fisher applications (the so-called KLUN project, for Kinematics of the Local Universe studies, end in 2008). The whole on-line HI archive of the NRT contains today reduced HI-profiles for ~4500 spiral galaxies of declination delta >-40{deg} (http://klun.obs-nancay.fr). As an example of application, we use direct Tully-Fisher relation in three (JHK) bands in deriving distances to a large catalog of 3126 spiral galaxies distributed through the whole sky and sampling well the radial velocity range between 0 and 8000km/s. Thanks to an iterative method accounting for selection bias and smoothing effects, we show as a preliminary output a detailed and original map of the velocity field in the Local Universe.
We present one of the deepest radio continuum surveys to date at a wavelength >~1m. The observations were taken with the VLA at 324.5MHz covering a region of the SWIRE Spitzer Legacy survey, centered at 10:46:00, +59:01:00 (J2000). The data reduction and analysis are described and an electronic catalog of the sources detected above 5{sigma} is presented. We also discuss the observed angular size distribution for the sample. Using our deeper 20cm survey of the same field, we calculate spectral indices for sources detected in both surveys.
This paper presents the first results of a 21cm survey of newly discovered optically selected galaxies behind the Milky Way. We present 40 radial velocities of the new galaxies and 15 velocities of UGC and MCG galaxies in a region where the well known Pisces-Perseus-Supercluster (PPScl) is supposed to be veiled by galactic extinction (80deg<~l<~110deg). Twenty-four galaxies have radial velocities between 4000 and 6000 km/s that fit to the values usually accepted for the PPScl. We could pursue this supercluster at least to b=-5 deg around l=90 deg.
Since the apparition of comet Kohoutek 1973 XII, the 18-cm lines of the OH radical have been systematically observed in a number of comets with the Nancay radio telescope. Between 1973 and 1999, 52 comets have been successfully detected. This allowed an evaluation of the cometary water production rates and their evolution with time, as well as a study of several physical processes such as the excitation mechanisms of the OH radio lines, the expansion of cometary atmospheres, their anisotropy in relation to non-gravitational forces, and the Zeeman effect in relation to the cometary magnetic field. Part of these observations and their analysis have already been published. The bulk of the results are now organized in a data base. The present paper is a general presentation of the Nancay cometary data base and a more specific description of the observations of 53 cometary apparitions between 1982 and 1999. Comets observed before 1982 are only partly incorporated in the data base. Observations of comets since 2000 have benefited from a major upgrade of the telescope; they will be presented in forthcoming publications.
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.
