Contingut
Imatges
Carregar la teva Imatge
DSS Images Other Images
Articles Relacionats
An IRAS High Resolution Image Restoration (HIRES) Atlas of All Interacting Galaxies in the IRAS Revised Bright Galaxy Sample
The importance of far-infrared observations for our understanding ofextreme activity in interacting and merging galaxies has beenillustrated by many studies. Even though two decades have passed sinceits launch, the most complete all-sky survey to date from which far-IRselected galaxy samples can be chosen is still that of the InfraredAstronomical Satellite (IRAS). However, the spatial resolution of theIRAS all-sky survey is insufficient to resolve the emission fromindividual galaxies in most interacting galaxy pairs, and hence previousstudies of their far-IR properties have had to concentrate either onglobal system properties or on the properties of very widely separatedand weakly interacting pairs. Using the HIRES image reconstructiontechnique, it is possible to achieve a spatial resolution ranging from30" to 1.5m (depending on wavelength and detector coverage), whichis a fourfold improvement over the normal resolution of IRAS. This issufficient to resolve the far-IR emission from the individual galaxiesin many interacting systems detected by IRAS, which is very importantfor meaningful comparisons with single, isolated galaxies. We presenthigh-resolution 12, 25, 60, and 100 μm images of 106 interactinggalaxy systems contained in the IRAS Revised Bright Galaxy Sample (RBGS,Sanders et al.), a complete sample of all galaxies having a 60 μmflux density greater than 5.24 Jy. These systems were selected to haveat least two distinguishable galaxies separated by less than threeaverage galactic diameters, and thus we have excluded very widelyseparated systems and very advanced mergers. Additionally, some systemshave been included that are more than three galactic diameters apart,yet have separations less than 4' and are thus likely to suffer fromconfusion in the RBGS. The new complete survey has the same propertiesas the prototype survey of Surace et al. We find no increased tendencyfor infrared-bright galaxies to be associated with other infrared-brightgalaxies among the widely separated pairs studied here. We find smallenhancements in far-IR activity in multiple galaxy systems relative toRBGS noninteracting galaxies with the same blue luminosity distribution.We also find no differences in infrared activity (as measured byinfrared color and luminosity) between late- and early-type spiralgalaxies.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| Molecular Gas in Strongly Interacting Galaxies. I. CO (1-0) Observations
We present observations of the CO (1-0) line in 80 interacting galaxiesas part of a program to study the role of interactions and mergers intriggering starbursts. The sample, which only includes obviouslyinteracting pairs of galaxies, is the largest such sample observed inCO. The observations were carried out at the NRAO 12 m and IRAM 30 mtelescopes. CO emission was detected in 56 galaxies (of which 32 are newdetections), corresponding to a detection rate of 70%. Because mostgalaxies are slightly larger than the telescope beam, correction factorswere applied to include CO emission outside the beam. The correctionfactors were derived by fitting a Gaussian function or an exponential CObrightness distribution to galaxies with multiple pointings and byassuming an exponential model for galaxies with single pointing. Wecompared the global CO fluxes of 10 galaxies observed by us at bothtelescopes. We also compared the measured fluxes for another 10 galaxiesobserved by us with those by other authors using the NRAO 12 m and FCRAO14 m telescopes. These comparisons provide an estimate of the accuracyof our derived global fluxes, which is ~40%. Mapping observations of twoclose pairs of galaxies, UGC 594 (NGC 317) and UGC 11175 (NGC 6621), arealso presented. In subsequent papers we will report the statisticalanalyses of the molecular properties in our sample galaxies and makecomparisons between isolated spirals and interacting galaxies.
| Kinematics of the local universe. VII. New 21-cm line measurements of 2112 galaxies
This paper presents 2112 new 21-cm neutral hydrogen line measurementscarried out with the meridian transit Nan\c cay radiotelescope. Amongthese data we give also 213 new radial velocities which complement thoselisted in three previous papers of this series. These new measurements,together with the HI data collected in LEDA, put to 6 700 the number ofgalaxies with 21-cm line width, radial velocity, and apparent diameterin the so-called KLUN sample. Figure 5 and Appendices A and B forcorresponding comments are available in electronic form at thehttp://www.edpsciences.com
| Kinematical Observations of a Sample of Binary Galaxies
Not Available
| The IRAS Bright Galaxy Survey - Part II: Extension to Southern Declinations (delta ~< -30), and Low Galactic Latitudes (f<|b|
Complete IRAS Observations and redshifts are reported for all sourcesidentified in the IRAS Bright Galaxy Survey-Part II (hereafter referredto as BGS_2_). Source positions, radial velocities, optical magnitudes,and total flux densities, peak flux densities, and spatial extents at12, 25, and 100 ,microns are reported for 288 sources having 60 micronflux densities > 5.24 Jy, the completeness limit of the originalBright Galaxy Survey [Soifer et al., AJ, 98,766(1989)], hereafterreferred to as BGS_1_. These new data represent the extension of theIRAS Bright Galaxy Survey to southern declinations,δ<~-30^deg^, and low Galactic latitudes,5^deg^<|b|<30^deg^. Although the sky coverage of the BGS_2_ (~19935 deg^2^) is 37% larger than the sky coverage of the BGS_1_, thenumber of sources is 8% smaller due primarily to large scale structurein the local distribution of galaxies. Otherwise, the sources in theBGS_2_ show similar relationships between number counts and flux densityas observed for the 313 sources in the BGS_1_. The BGS_2_ along with theearlier BGS, represents the best sample currently available for definingthe infrared properties of galaxies in the local (z <~ 0.1) Universe.
| Observations of binary galaxies at a frequency of 102 MHz
A total of 93 double galaxies from the Karachentsev list was observedwith the large phased array at the Lebedev Physical Institute at 102MHz. The interplanetary oscillation method was used. Two of the galaxieswere found to contain scintillating components with angular dimensionsof less than 1 arcsec and flux densities of more than 1 Jy. Theobservations of double galaxies at low radio frequencies indicate thatgalaxies in pairs are more active than single galaxies.
| IRAS observations of an optically selected sample of interacting galaxies
IRAS observations of a large, morphologically selected sample ofstrongly interacting disk-type galaxies have demonstrated thatgalaxy-galaxy collisions can lead to enhanced infrared emission, but notin all cases. Infrared luminosities of the interacting galaxies span alarge range, but are about a factor of 2 higher, on average, than thoseof isolated disk galaxies. The data suggest the existence of a cutoff inblue luminosity, below which no galaxies show markedly enhanced infraredemission. Only the most strongly interacting systems in the sample showextreme values of infrared excess, suggesting that deep,interpenetrating collisions are necessary to drive infrared emission toextreme levels. Comparisons with optical indicators of star formationshow that infrared excess and color temperatures correlate with thelevel of star-formation activity in the interacting galaxies. Allinteracting galaxies in our sample that exhibit an infrared excess andhave higher than normal color temperatures also have optical indicatorsof high levels of star formation. It is not necessary to invokeprocesses other than star formation to account for the enhanced infraredluminosity in this sample of interacting galaxies.
| Global properties of interacting disk-type galaxies
Optical, far-IR, and radio observations of global properties arepresented for a sample of strongly interacting disk-type galaxies.Global star formation rates (SFRs) for the galaxies span a large rangeand are, on average, a factor of 2.5 higher than similarly determinedglobal SFRs for isolated spiral galaxies. New star formation occurspreferentially in or near the nuclear regions. H I 21 cm emission-lineprofiles indicate the presence of anomalous velocity material andchaotic patterns of gas motion in many interacting systems. Few systemsshow evidence for the presence of a well-organized rotating H I disksuch as are seen in isolated spiral galaxies. Neutral hydrogen gasmass-to-blue luminosity ratios are not atypical when compared withisolated spirals. The evidence indicates that local rather than globalproperties of these galaxies govern the star-formation process. Theobservations generally support the notion that enhanced SFRs are causedby increased cloud collision rates and dissipative flows of gas to thenucleus.
| High signal-to-noise ratio observations of H I in 243 galaxies
The 21 cm spectral-line system of the Arecibo Observatory was used tomeasure neutral hydrogen emission from 243 faint galaxies. Most lie nearthe plane of the Local Supercluster. All observations reach anunsmoothed signal-to-noise ratio of at least 7.0; the average for theset is 23. The resulting data are used to estimate H I masses, systemicvelocities, and accurate profile widths at 20 percent, 25 percent, 50percent, and 80 percent of peak intensity levels. The widths are used tocalibrate directly the bias introduced by popular data-smoothingoperation. The data include observations of 65 objects with previouslyunknown redshifts.
| The bivariant luminosity function for isolated galaxy pairs
The radio observations of Stocke et al. (1978) on isolated galaxy pairsfrom the catalog of Karachentsev (1972) are analyzed using the method ofArakelyan (1984) to calculate the optical/radio bivariant luminosityfunctions (BLFs). The results are presented in tables and graphs andcharacterized statistically. The discrepancy between the BLFs of type EEpairs and those of ES/SE or SS pairs is attributed to pseudopairing inthe EE pairs, and the number density of the radio pairs is found to beabout 0.0004/cu Mpc, as compared to 0.004/cu Mpc for all pairedgalaxies.
| A 21 centimeter line survey of a complete sample of interacting and isolated galaxies
The paper presents 21 cm line observations of a complete sample ofinteracting and isolated galaxies made with the National Radio AstronomyObservatory 91 and 43 m telescopes and the Arecibo 3035 m telescope. The21 cm line data are combined with a homogeneous set of optical data onangular diameters, axial ratios, magnitudes, and colors, and integralproperties are calculated for the galaxies in both samples. In thispaper, the sample selection procedures, the method of observation, thedata reduction, and the observational errors are described. Thedetection percentages are presented for both samples.
| Radial velocities of double galaxies
Spectral observations of 92 galaxies in isolated pairs have been carriedout. In 52 cases radial velocities were measured. The mean value of theorbital mass-to-luminosity ratio for 18 pairs is (16.2 plus or minus10.0) times the solar value.
|
Enviar un nou article
Enllaços Relacionats
- - No s'ha trobat enllaços -
Enviar un nou enllaç
Membre dels grups següents:
|
Dades d'Observació i Astrometria
Catàlegs i designacions:
|
