Infrared photometric study of SDSS selected narrow line Seyfert 1 galaxies

The infrared photometric study of SDSS selected Narrow Line Seyfert 1 Galaxies (NLS1s) is presented in this paper. We have made cross-identifications for such NLS1s with 2MASS and WISE observations. Finally 992 NLS1s have 2MASS and WISE counterparts. Comparisons of NLS1s with the Broad Line Seyfert 1 (BLS1s) and Seyfert 2 galaxies are made. It is shown that from 1 µm to 5 µm NLS1s are redder than BLS1s and Seyfert 2 galaxies possibly due to the richer dust environment in NLS1 nuclei or to the orientation effect while in the longer wavelengths those three kinds of sources have quite similar behavior indicative of radiation mainly from the similar warm starburst-related dust and the related AGN dust.In addition, relations between infrared colors and related (to H_β) strengths of some important lines are also investigated. The results show that the related strengths of [FeII] 4570 Å are positively correlated with infrared colors in the 1–5 µm region, but negatively correlated with infrared colors in the 12–22 µm region; the related strength of [OIII] 5007 Å are negatively correlated with infrared colors in the 1–5 µm region, but positively correlated with infrared colors in the 12–22 µm region; the related strength of [NII]6583 Å are also negatively correlated with infrared colors in the 1–5 µm region, but positively correlated with infrared colors in the 12–22 µm region. Therefore it is indicated that the behavior of [FeII] 4570 Å is just opposed to that for [OIII] 5007 Å and [NII] 6583 Å This result may be caused by different origins of such lines.     

A photometric study of poor clusters of galaxies

Sixteen poor clusters of galaxies with suspected cD galaxies are studied usingV-band photographs taken with the 105 cm Kiso Schmidt telescope. Galaxian images were automatically detected using an image detection software developed for the present study. It is found from the luminosity functions that the richness of the clusters are well correlated with the optical properties of central galaxies and the X-ray luminosities of the clusters.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Infrared emission of dust grains in the clusters of galaxies

The observations of the reddening of the distant galaxies and the weak diffuse radiation in the clusters of galaxies can be interpreted as a consequence of the presence of dust grains in the intergalactic medium. When allowance is made for the destruction of the grains in collision with particles of the hot gas, its lifetime is about 10⁷–10⁸ yr at a gas concentrationn _g 10^–3 cm^–3. The detection of the infrared (IR) emission from the galaxy clusters might be the test for the proof of the presence of dust grains in the intergalactic medium. In this paper the estimates of the expected intensities and fluxes of IR emission for the spectral region 50–300 are presented for two galaxy clusters in Coma and Perseus. The parameters of the hot gas spatial distribution are chosen from X-ray observations. Having assumed that intergalactic dust can be ejected only from the galaxies, we used such a model for intergalactic dust grains which explains very well the interstellar dust effects. It is shown that the dust temperature, which is determined from the general energetic balance of the dust grains, can achieve some scores of degrees of Kelvin. Two models of the dust spatial distribution are considered. It is found that the maximum of IR flux for the Coma cluster lies near =100 and the same for the Perseus cluster near 50–70. The total fluxes of IR emission from these clusters are about 10⁵–10⁶ Jy and can be detected by modern observational methods.     

Infrared photometric study of type II quasars

For this paper, we collected almost all of the type II quasars so far discovered. Among them, 485 sources have photometric data at JHK bands, mainly from Two-Micron All-Sky Survey observations, 65 sources have IRAS photometric data in at least one of the three IRAS bands at 25, 60 and 100 μm and 15 sources have IRAS photometric data in all three IRAS bands. We find that in nearly half of all type II quasars, both the near- and far-infrared radiations are dominated by starlight or thermal reprocessing of starlight by dust in the underlying galaxy. The infrared radiation of the other group (slightly over half) is dominated by a non-thermal radiation in the near-infrared, and mostly in the far-infrared also (although there is a mixture particularly for the longer wavelengths). It is proposed that for the later group, hidden broad lines may exist in the infrared. On the basis of our and previous results, we also discuss the possibility that there are two distinct classes of type II quasars: 'true' type II quasars without a broad-line region and heavily obscured type I quasars, in full analogy with the case for type II Seyfert galaxies. No relationships can be found for either the near-infrared or the far-infrared colours and the redshift. Correlations between absolute magnitude in the near- and far-infrared with redshift are found, but could be due to a flux limit (Malmquist bias).     

Spectral and photometric study of compact groups of compact galaxies

Results are presented from a spectral, photometric, and morphological study of two compact groups of compact galaxies (CGCG) from Shahbazian’s list. The observations were made on the 1.5-m ESO telescope and the 2.6-m telescope at the Byurakan Astrophysical Observatory (BAO) during 1999–2000. These data are compared with data for the Shahbazian compact group 4. A high spatial density of galaxies, ranging from 10000 to 100000 galaxies per Mpc³, is observed in all the groups that were studied. The discovery of a Seyfert Sy1 galaxy in the Shahbazian 355 compact group is especially noteworthy. The direct photographs of the CGCGs that were studied contain no signs of merging or tidal interactions among the members of these groups. This suggests that the galaxies in these dense systems have a common origin. __________ Translated from Astrofizika, Vol. 50, No. 3, pp. 347–353 (August 2007).     

Two-colour photometric selection of high-redshift galaxies

In this paper we describe a set of models to predict the colours of galaxies over a wide range of redshifts. We present examples of output from the simulations, and discuss their application to the selection of galaxies at high redshifts, particularly through identification of the Lyman break. Additionally we consider the optimal choices of filters for selection at a range of redshifts.
An interface to a subset of the simulations has been made available on the World Wide Web for the benefit of the community at the location http://www-astro.physics.ox.ac.uk/~rejs/research/galcols.html/     

IRAC photometric analysis and the mid-IR photometric properties of Lyman-break galaxies

We present photometric analysis of deep mid-infrared (mid-IR) observations obtained by Spitzer /IRAC covering the fields Q1422+2309, Q2233+1341, DSF2237a,b, HDFN, SSA22a,b and B20902+34, giving the number counts and the depths for each field. In a sample of 751 Lyman-break galaxies (LBGs) lying in those fields, 443, 448, 137 and 152 are identified at 3.6-, 4.5-, 5.8-, 8.0-μm IRAC bands, respectively, expanding their spectral energy distribution to rest-near-IR and revealing that LBGs display a variety of colours. Their rest-near-IR properties are rather inhomogeneous, ranging from those that are bright in IRAC bands and exhibit  [ R ]−[3.6] > 1.5  colours to those that are faint or not detected at all in IRAC bands with  [ R ]−[3.6] < 1.5  colours and these two groups of LBGs are investigated. We compare the mid-IR colours of the LBGs with the colours of star-forming galaxies and we find that LBGs have colours consistent with star-forming galaxies at   z ∼ 3  . The properties of the LBGs detected in the 8-μm IRAC band (rest-frame K band) are examined separately, showing that they exhibit redder  [ R ]−[3.6]  colours than the rest of the population and that although in general, a multiwavelength study is needed to reach more secure results, IRAC 8-μm band can be used as a diagnostic tool, to separate high z , luminous AGN-dominated objects from normal star-forming galaxies at   z ∼ 3  .     

A photometric study of faint galaxies in the field of GRB 000926

We present our B, V, R_c, and I_c observations of a \(3'.6 \times 3'\) field centered on the host galaxy of GRB 000926 (α_2000.0=17^h04^m11^s, \(\delta _{2000.0} = + 51^ \circ 47'9\mathop .\limits^{''} 8\)). The observations were carried out on the 6-m Special Astrophysical Observatory telescope using the SCORPIO instrument. The catalog of galaxies detected in this field includes 264 objects for which the signal-to-noise ratio is larger than 5 in each photometric band. The following limiting magnitudes in the catalog correspond to this limitation: 26.6 (B), 25.7 (V), 25.8 (R), and 24.5 (I). The differential galaxy counts are in good agreement with previously published CCD observations of deep fields. We estimated the photometric redshifts for all of the cataloged objects and studied the color variations of the galaxies with z. For luminous spiral galaxies with M(B)z～1.     

Maximum dust masses in galaxies

The large dust masses apparently present in some galaxies at high redshift prompt the question of just how much interstellar dust can be present per unit mass of a galaxy. Under very simple assumptions, we derive an upper limit to this mass — showing both what is possible for a galaxy of given total mass and various gas fractions, and what represents the ultimate upper limit for a given stellar or total mass, if we are free to choose the particular gas fraction. The results hold for a galaxy formed with arbitrary gas outflows, or arbitrary inflows of unenriched gas, and illustrate the difficulty of generating very high dust masses in galaxies.     

Infrared luminosities of local-volume galaxies

Based on data from the Two-Micrometer All-Sky Survey (2MASS), we analyzed the infrared properties of 451 Local-Volume galaxies at distances D ≤ 10 Mpc. We determined the K-band luminosity function of the galaxies in the range of absolute magnitudes from ?25^m to ?11^m. The local luminosity density within 8 Mpc is 6.8 × 10⁸L_⊙ Mpc^?3, a factor of 1.5 ± 0.1 higher than the global mean K-band luminosity density. We determined the ratios of the virial mass to the K-band luminosity for nearby groups and clusters of galaxies. In the luminosity range from 5 × 10¹⁰ to 2 × 10¹³L_⊙, the dependence log(M/L_K) ∝ (0.27 ± 0.03) log L_K with a dispersion of ～0.1 comparable to the measurement errors of the masses and luminosities of the systems of galaxies holds for the groups and clusters of galaxies. The ensemble-averaged ratio, 〈M/L_K〉 ? (20–25) M_⊙/L_⊙, was found to be much smaller than the expected global ratio, (80–90)M_⊙/L_⊙, in the standard model with Ω_m = 0.27. This discrepancy can be eliminated if the bulk of the dark matter in the Universe is not associated with galaxies and their systems.     

Studying the dwarf galaxies in nearby groups of galaxies: Spectroscopic and photometric data

Galaxy evolution by interaction‐driven transformation is probably highly efficient in groups of galaxies. Dwarf galaxies with their shallow potential are expected to reflect the interaction most prominently in their observable structure. The major aim of this series of papers is to establish a data base which allows to study the impact of group interaction onto the morphology and star‐forming properties of dwarf galaxies. Firstly, we present our selection rules for target groups and the morphological selection method of target dwarf member candidates. Secondly, the spectroscopic follow‐up observations with the HET are presented. Thirdly, we applied own reduction methods based on adaptive filtering to derive surface photometry of the candidates. The spectroscopic follow‐up indicate a dwarf identification success rate of roughly 55 %, and a group member success rate of about 33 %. A total of 17 new low surface‐brightness members is presented. For all candidates, total magnitudes, colours, and light distribution parameters are derived and discussed in the context of scaling relations. We point out short comings of the SDSS standard pipeline for surface photometry for these dim objects. We conclude that our selection strategy is rather efficient to obtain a sample of dim, low surface brightness members of groups of galaxies within the Virgo super‐cluster. The photometric scaling relation in these X‐ray dim, rather isolated groups does not significantly differ from those of the galaxies within the local volume. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Infrared galaxies in compact groups

IR properties of Compact Group (CG) galaxies are presented and compared with IR properties of isolated galaxies. Despite CGs displaying more E-S0s and optically bright galaxies, no differences are retrieved concerning FIR emission. The observed lack of strong FIR enhancement in the CG sample is not surprising when interpreting FIR sources in CGs as accordant redshift projections, rather than as mergers in progress. This revised version was published online in August 2006 with corrections to the Cover Date.     

Catalogue of non-Abell clusters of galaxies with published photometric data

This catalogue is a compilation of references of publications with photometric data in and around non-Abell clusters of galaxies.     

Infrared spectra of cooling flow galaxies

We have taken K -band spectra covering seven cooling flow clusters. The spectra show many of the 1-0S transitions of molecular hydrogen, as well as some of the higher vibrational transitions, and some lines of ionized hydrogen. The line ratios allow us to conclude that the rotational states of the first excited vibrational state are in approximate local thermodynamic equilibrium (LTE), so that densities above 10⁵ cm⁻³ are likely, but there is evidence that the higher vibrational states are not in LTE. The lack of pressure balance between the molecular gas and the ionized components emphasizes the need for dynamic models of the gas. The ratios of the ionized to molecular lines are relatively constant but lower than from starburst regions, indicating that alternative heating mechanisms are necessary.     

Catalogue of Abell clusters of galaxies with published photometric data

This catalogue is a compilation of references of publications with photometric data in and around Abell clusters of galaxies. Die Arbeit enthält eine Zusammenstellung der Publikationen mit photometrischen Daten für Abell-Haufen und ihre Umgebung.