Spectrophotometric properties of galaxies at intermediate redshifts (z~ 0.2--1.0) I. Sample description, photometric properties and spectral measurements (original) (raw)

The Hamburg/SAO survey for emission-line galaxies. VI. The sixth list of 126 galaxies

Astronomy & Astrophysics, 2005

We present the fifth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO -- Special Astrophysical Observatory, Russia). The list is a result of follow-up spectroscopy conducted with the 2.2m CAHA and 4m Kitt Peak telescopes in 1999. The data of this snap-shot spectroscopy survey confirmed 166 emission-line objects out of 209 observed candidates and allowed their quantitative spectral classification and redshift determination. We could classify 98 emission-line objects as BCG/HII galaxies or probable BCGs, 5 -- as QSOs, 3 - as Seyfert galaxies, 2 - as super-associations in subluminous spiral galaxies. 25 low-excitation objects were classified as starburst nuclei (SBN), 24 as dwarf amorphous nuclei starburst galaxies (DANS) and 3 as LINERs. Due to low signal-to-noise ratio we could not classify 6 ELGs. Furthermore, for another 4 galaxies we did not detect any significant emission lines. For 131 emission-line galaxies, the redshifts and/or line intensities are determined for the first time. For the remaining 30 previously known ELGs we give either improved data of the line intensities or some independent measurements.

The Hamburg/SAO survey for emission-line galaxies . V. The fifth list of 161 galaxies

Astronomy & Astrophysics, 2001

We present the sixth list with results ⋆⋆ of the Hamburg/SAO Survey for Emission-Line Galaxies. The final list resulted from follow-up spectroscopy conducted with the 4.5 m MMT telescope in 1996, and with 2.2 m CAHA and 6 m SAO telescopes in 2000 to 2003. The data of this snap-shot spectroscopy survey confirmed 134 emission-line objects out of 182 observed candidates and allowed their quantitative spectral classification and redshift determination. We classify 73 emission-line objects as definite or probable blue compact or Hii galaxies (BCG), 8 as QSOs, 4 as Seyfert 1 and 2 galaxies. 30 low-excitation objects were classified as definite or probable starburst nuclei (SBN), 3 as dwarf amorphous nuclei starburst galaxies (DANS) and 2 as LINERs. Due to the low signal-to-noise ratio we could not classify 14 ELGs (NON). For another 9 galaxies we did not detect any significant emission lines. For 98 emission-line galaxies, the redshifts and/or line intensities are determined for the first time. For the remaining 28 previously-known ELGs we give either improved data the line intensities or some independent measurements. The detection rate of ELGs is ∼70%. This paper completes the classification of strong-lined ELGs found in the zone of the Hamburg/SAO survey. Together with previously known BCG/H ii galaxies in this zone, this sample of ∼500 objects is the largest to date in a well bound region.

The Canada-France Redshift Survey - XII. Nature of emission-line field galaxy population up to z=0.3

Monthly Notices of the Royal Astronomical Society, 1996

We present a spectroscopic study of the 138 field galaxies to a redshift z=0.3 from the I-selected Canada-France Redshift Survey. 117 (85 per cent) spectra exhibit at least Hα in emission, and the remaining 21 (15 per cent) are purely absorption-line spectra. We focus our analysis on spectra with Hα and Hβ in emission, accounting for about half of this low-z sample, which we classify using emission-line ratio diagrams. Using photoionization models, we determine the extreme boundaries of HII galaxies in these diagnostic diagrams, and demonstrate that the emission-line ratios of a significant fraction of galaxies require harder photoionization sources than massive O stars. We find that about 17 per cent of the field galaxies have emission-line ratios consistent with active galaxies, e.g., Seyfert 2 or LINERs. After correcting for stellar absorption under the Balmer lines, we conclude that the fraction of such galaxies is at least 8 per cent of the field galaxy population at z<=0.3.

The Hamburg/SAO survey for emission-line galaxies . III. The third list of 81 galaxies

Astronomy & Astrophysics Supplement Series, 2000

The follow-up spectroscopy with the 2 m class telescopes confirmed 85 emission-line objects out of 113 observed candidates and allowed their quantitative spectral classification. For 80 of them, the redshifts are determined for the first time. For 5 previously known ELGs, line ratios are presented for the first time. We could classify 55 out of the 85 emission-line objects as BCG/H{\sc ii} galaxies or probable BCGs, 4 - as QSOs, 6 - as Seyfert galaxies, 1 - as super-association in a subluminous spiral galaxy, and 11 are low-excitation objects - either starburst nuclear (SBN), or dwarf amorphous nuclear starburst galaxies (DANS). We could not classify 8 ELGs. Further, for 8 more galaxies we did not detect any significant emission lines.

Spectral classification of emission-line galaxies from the Sloan Digital Sky Survey

Astronomy & Astrophysics, 2011

Aims. We study the spectral classification of emission-line galaxies as starforming galaxies or active galactic nuclei (AGNs). With the high-quality data from the Sloan Digital Sky Survey (SDSS) we define an improved classification to be used for high-redshift galaxies. Methods. We classify emission-line galaxies of the SDSS according to the latest standard recipe using [Oiii]λ5007, [Nii]λ6584, [Sii]λ6717+6731, Hα, and Hβ emission lines. We obtain four classes: starforming galaxies, Seyfert 2, LINERs, and composites. We then examine where these galaxies fall in the blue diagram used at high redshift (i.e. log([Oiii]λ5007/Hβ) vs. log([Oii]λλ3726+3729/Hβ). Results. We define new improved boundaries in the blue diagram for starforming galaxies, Seyfert 2, LINERs, SF/Sy2, and SF-LIN/comp classes. We maximize the success rate to 99.7% for the detection of starforming galaxies to 86% for the Seyfert 2 (including the SF/Sy2 region) and to 91% for the LINERs. We also minimize the contamination to 16% in the region of starforming galaxies. We cannot reliably separate composites from starforming galaxies and LINERs, but we define an SF-LIN/comp region where most of them fall (64%).

Spectrophotometry of Nearby Field Galaxies: The Data

The Astrophysical Journal Supplement Series, 2000

We have obtained integrated and nuclear spectra, as well as U, B, R surface photometry, for a representative sample of 196 nearby galaxies. These galaxies span the entire Hubble sequence in morphological type, as well as a wide range of luminosities (M B = −14 to −22). Here we present the spectrophotometry for these galaxies. The selection of the sample and the U, B, R surface photometry is described in a companion paper (Paper I). Our goals for the project include measuring the current star formation rates and metallicities of these galaxies, and elucidating their star formation histories, as a function of luminosity and morphology. We thereby extend the work of Kennicutt (1992a) to lower luminosity systems. We anticipate that our study will be useful as a benchmark for studies of galaxies at high redshift.

Survey for Emission‐Line Galaxies: Universidad Complutense de Madrid List 3

The Astrophysical Journal Supplement Series, 1999

A new low-dispersion objective-prism search for low-redshift (z < 0.045) emission-line galaxies (ELG) has been carried out by the Universidad Complutense de Madrid with the Schmidt Telescope at the Calar-Alto Observatory. This is a continuation of the UCM Survey, which was performed by visual selection of candidates in photographic plates via the presence of the Hα + [NII]λ6584 blend in emission. In this new list we have applied an automatic procedure, fully developed by us, for selecting and analyzing the ELG candidates on the digitized images obtained with the MAMA machine. The analyzed region of the sky covers 189 square degrees in nine fields near α = 14 h & 17 h , δ = 25 • . The final sample contains 113 candidates. Special effort has been made to obtain a large amount of information directly from our uncalibrated plates by using several external calibrations. The parameters obtained for the ELG candidates allow for the study of the statistical properties for the sample.

The Hamburg/SAO survey for emission-line galaxies. IV. The fourth list of 119 galaxies

Astronomy & Astrophysics, 2001

We present the fourth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS hereafter, SAO - Special Astrophysical Observatory, Russia). The list is a result of the follow-up spectroscopy conducted with the 6 m SAO RAS telescope in 1998, 1999 and 2000. The data of this snap-shot spectroscopy survey confirmed 127 emission-line objects out of 176 observed candidates and allowed their quantitative spectral classification. We could classify 76 emission-line objects as BCG/Hii galaxies or probable BCGs, 8 - as QSOs, 2 - as Seyfert galaxies, 2 - as super-associations in a subluminous spiral and an irregular galaxy, and 37 as low-excitation objects - either starburst nuclei (SBN), or dwarf amorphous nuclei starburst galaxies (DANS). We could not classify 2 ELGs. Furthermore, for 5 galaxies we did not detect any significant emission lines. For 91 emission-line galaxies, the redshifts and/or line intensities are determined for the first time. Of the remaining 28 previously known ELGs we give either improved data on the line intensities or some independent measurements. The candidates were taken from three different samples selected by different criteria. Among our first priority candidates we achieved a detection rate of emission-line objects (ELGs + QSOs) of 68%, among which 51% are BCGs. Observations of a random selected sample among our second priority candidates showed that only ~10% are BCGs. We found that the confirmed BCGs have usually a blue colour ((B-R) < 1\fm0) and a non-stellar appearance in the APM database. Our third sample is comprised of second priority candidates fulfilling these criteria derived from the APM. Follow-up spectroscopy of a small subsample indicates that the expected detection rate for BCGs is ~40%. Tables 3 to 8 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/366/771 Figures A1 and A12 are only available in electronic form at http://www.edpsciences.org

New diagnostic methods for emission-line galaxies in deep surveys

Monthly Notices of the Royal Astronomical Society, 1997

We present new quantitative classification methods for emission-line galaxies, which are specially designed to be used in deep galaxy redshift surveys. A good segregation between starbursts and active galactic nuclei, i.e. Seyferts 2 and LINERs, is obtained from diagnostic diagrams involving the [O II]λ3727Å, [Ne III]λ3869Å, Hβ and [O III]λ5007Å relative intensities or the [O II]λ3727Å and Hβ equivalent widths. Furthermore, the colour index of the continuum underlying [O II]λ3727Å

The CIDA-UCM-Yale shallow survey for emission-line galaxies

Monthly Notices of The Royal Astronomical Society, 2005

We present the CIDA-UCM-Yale (Centro de Investigaciones de Astronomía, Universidad Complutense de Madrid and Yale University) survey for Hα + [NII]6549, 6584 emission-line galaxies using objective-prism spectra. The most important properties of a catalogue with 427 entries and significant subsets are analysed. The complete sample contains 183 statistically confirmed ELGs in a sky area of 151 deg 2 and redshift up to 0.14. We determine the parameters of the Hα luminosity function using the Hα + [NII] flux directly measured on the ELGs spectra in this sample and the star formation rate density derived is in agreement with the values reported in the literature. Finally, we study the clustering properties of local star-forming galaxies relative to quiescent ones from different perspectives. We find that emission-line galaxies avoid dense regions of quiescent galaxies and we propose a power-law expression to parametrise the relation between star formation rate density and environment volume density of emission-line galaxies.