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A Chandra Snapshot Survey of Infrared-bright LINERs: A Possible Link Between Star Formation, Active Galactic Nucleus Fueling, and Mass Accretion
We present results from a high-resolution X-ray imaging study of nearbyLINERs observed by ACIS on board Chandra. This study complements andextends previous X-ray studies of LINERs, focusing on the underexploredpopulation of nearby dust-enshrouded infrared-bright LINERs. The sampleconsists of 15 IR-bright LINERs (LFIR/LB>3),with distances that range from 11 to 26 Mpc. Combining our sample withprevious Chandra studies, we find that ~51% (28/55) of the LINERsdisplay compact hard X-ray cores. The nuclear 2-10 keV luminosities ofthe galaxies in this expanded sample range from ~2×1038to ~2×1044 ergs s-1. We find that the mostextreme IR-faint LINERs are exclusively active galactic nuclei (AGNs).The fraction of LINERs containing AGNs appears to decrease with IRbrightness and increase again at the highest values ofLFIR/LB. We find that of the 24 LINERs showingcompact nuclear hard X-ray cores in the expanded sample that wereobserved at Hα wavelengths, only eight actually show evidence of abroad line. Similarly, of the 14 LINERs showing compact nuclear hardX-ray cores with corresponding radio observations, only eight display acompact flat spectrum radio core. These findings emphasize the need forhigh-resolution X-ray imaging observations in the study of IR-brightLINERs. Finally, we find an intriguing trend in the Eddington ratioversus LFIR and LFIR/LB for theAGN-LINERs in the expanded sample that extends over 7 orders ofmagnitude in L/LEdd. This correlation may imply a linkbetween black hole growth, as measured by the Eddington ratio, and thestar formation rate, as measured by the far-IR luminosity andIR-brightness ratio. If the far-IR luminosity is an indicator of themolecular gas content in our sample of LINERs, our results may furtherindicate that the mass accretion rate scales with the host galaxy's fuelsupply. We discuss the potential implications of our results in theframework of black hole growth and AGN fueling in low-luminosity AGNs.
| Physical Coupling of Kazarian Galaxies with Surrounding Galaxies
Results from a statistical study of Kazarian galaxies and the objectssurrounding them are presented. It is shown that: (1) the sample ofKazarian galaxies up to 16m.0 is complete. (2) Roughly 35.7% of theKazarian galaxies are members of clusters, 14.0% of groups, and 13.6% ofbinary systems, while 36.7% are single galaxies. (3) Of the 580 Kazariangalaxies, roughly 61.2% are infrared, 8.8% radio, and 2.8% x-raysources. (4) The relative numbers of Kazarian galaxies for completesamples of I, R, and X in the different groups are systematically higherthan the corresponding numbers for samples of all Kazarian galaxies.
| Hydrogen content in Kazarian galaxies
Several H I related astrophysical parameters such as neutral hydrogentotal mass and hydrogen mean projected density, indicative total mass aswell as usual ratios MH/L0,MH/Mi and Mi/L0 for 23galaxies from Kazarian lists are derived. Their variation ranges arerather wide almost coinciding with those for normal galaxies belongingto the same morphological types. Kazarian galaxies do not constitute ahomogeneous sample by any of the commonly used H I related parameters.Comparison with Markarian and blue Haro galaxies demonstrate thatKazarian galaxies have quite similar H I properties and contain ratherhigh relative numbers (~30%) of peculiar objects. Brief comments on thepeculiar galaxies Kaz 63, Kaz 65, Kaz 69 and Kaz 211 are given.
| 21-cm line observations of galaxies from Kazarian's lists
The 21-cm neutral hydrogen line has been measured for the first time in39 non-Seyfert type galaxies from Kazarian list, with the Nancayradiotelescope. The line profiles, widths at 20% and 50% of the peakintensity, radial velocities as well as total fluxes are presented. Thevalues of radial velocity are in fairly good agreement with thoseobtained from optical spectra. The width values at 20% of the peak varyin wide range from 113 km s^{-1} (KAZ 579) to 608 km s^{-1} for KAZ 566.Nine of our objects remained undetected, whether their HI-flux was toofaint, the integration time too short, or the frequency sighted wrong.However, for part of them, there were positive hint of detection.Comments on individual objects are given. Tables 1 and 3 are onlyavailable in electronic form at CDS. Table 2 is also available inelectronic form at CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Morphological classification of new galaxies with a UV excess
The results of a morphological classification of 580 galaxies with a UVexcess, included in the lists in [M. A. Kazarian, Astrofizika,15, 5(1979); ibid.,15, 193 (1979); M. A. Kazarian and É. S. Kazarian,ibid.,16, 17 (1980); ibid.,18, 512 (1982); ibid.,19, 213 (1983)], arepresented. For this we have developed a set of symbols, using the typesE, S, and Ir introduced by Hubble, as well as symbols introduced byother authors and us. This set enabled us to make the morphologicalclassification. Direct photographs obtained on the 2.6-m and 6-mtelescopes were used to classify 141 of the galaxies (over 24%), whilePalomar Atlas charts were used for the remaining 439 galaxies. Thesegalaxies were divided into two groups based on classificationconditions, and data on each group are given in Tables 1 and 2,respectively. The results for each group, given in Table 3, show thatwith the transition from early types, such as C and E, to later types,such as S and Ir, the relative number of galaxies going into one group(Table 1), in which the classification was based on direct photographs,increases in comparison with the number going into the other group(Table 2).
| Spectrophotometry and morphology of the galaxies with UV excess. III.
Not Available
| Spectral observations of new galaxies with UV excess. II
Results of spectral observations of 41 galaxies with UV excess arepresented. The spectra were obtained with the 6-m telescope of theSpecial Astrophysicl Observatory. Emission lines were observed in thespectra of 36 galaxies. Four objects, 147, 214, 323, and 336 are of theSeyfert type (Sy 2), while one galaxy, 238, is a Seyfert candidate.
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