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|[O II] as a Star Formation Rate Indicator|
We investigate the [O II] emission line as a star formation rate (SFR)indicator using integrated spectra of 97 galaxies from the Nearby FieldGalaxies Survey (NFGS). The sample includes all Hubble types andcontains SFRs ranging from 0.01 to 100 Msolaryr-1. We compare the Kennicutt [O II] and Hα SFRcalibrations and show that there are two significant effects thatproduce disagreement between SFR([O II]) and SFR(Hα): reddeningand metallicity. Differences in the ionization state of the interstellarmedium do not contribute significantly to the observed differencebetween SFR([O II]) and SFR(Hα) for the NFGS galaxies withmetallicities log(O/H)+12>~8.5. The Kennicutt [O II]-SFR relationassumes a typical reddening for nearby galaxies; in practice, thereddening differs significantly from sample to sample. We derive a newSFR([O II]) calibration that does not contain a reddening assumption.Our new SFR([O II]) calibration also provides an optional correction formetallicity. Our SFRs derived from [O II] agree with those derived fromHα to within 0.03-0.05 dex. We show that the reddening, E(B-V),increases with intrinsic (i.e., reddening-corrected) [O II] luminosityfor the NFGS sample. We apply our SFR([O II]) calibration withmetallicity correction to two samples: high-redshift 0.8
|The Hα and Infrared Star Formation Rates for the Nearby Field Galaxy Survey|
We investigate the Hα and infrared star formation rate (SFR)diagnostics for galaxies in the Nearby Field Galaxy Survey (NFGS). Forthe 81 galaxies in our sample, we derive Hα fluxes (included here)from integrated spectra. There is a strong correlation between the ratioof far-infrared to optical luminosities L(FIR)/L(Hα) and theextinction E(B-V) measured with the Balmer decrement. Before reddeningcorrection, the SFR(IR) and SFR(Hα) are related to each other by apower law: SFR(IR)=(2.7+/-0.3)SFR(Hα)1.30+/-0.06.Correction of the SFR(Hα) for extinction using the Balmerdecrement and a classical reddening curve both reduces the scatter inthe SFR(IR)-SFR(Hα) correlation and results in a much closeragreement between the two SFR indicators;SFR(IR)=(0.91+/-0.04)SFR(Hαcorr)1.07+/-0.03.SFR(IR) and SFR(Hα) agree to ~10%. This SFR relationship spans 4orders of magnitude and holds for all Hubble types with IRAS detectionsin the NFGS. A constant ratio between the SFR(IR) and SFR(Hα) forall Hubble types, including early types (S0-Sab), suggests that the IRemission in all these objects results from a young stellar population.
|Starbursts versus Truncated Star Formation in Nearby Clusters of Galaxies|
We present long-slit spectroscopy, B- and R-bandpass imaging, and 21 cmobservations of a sample of early-type galaxies in nearby clusters,which are known to be either in a star-forming phase or to have had starformation that recently terminated. From the long-slit spectra, obtainedwith the Blanco 4 m telescope, we find that emission lines in thestar-forming cluster galaxies are significantly more centrallyconcentrated than in a sample of field galaxies. The broadband imagingreveals that two currently star-forming early-type galaxies in thePegasus I cluster have blue nuclei, again indicating that recent starformation has been concentrated. In contrast, the two galaxies for whichstar formation has already ended show no central color gradient. ThePegasus I galaxy with the most evident signs of ongoing star formation(NGC 7648), exhibits signatures of a tidal encounter. Neutral hydrogenobservations of that galaxy with the Arecibo radio telescope reveal thepresence of ~4×108 Msolar of H I. Areciboobservations of other current or recent star-forming early-type galaxiesin Pegasus I indicate smaller amounts of gas in one of them, and onlyupper limits in others. These observations indicate that NGC 7648 in thePegasus I cluster owes its present star formation episode to some formof tidal interaction. The same may be true for the other galaxies withcentralized star formation, but we cannot rule out the possibility thattheir outer disks have been removed via ram pressure stripping, followedby rapid quenching of star formation in the central region.
|Spectrophotometry of Nearby Field Galaxies: The Data|
We have obtained integrated and nuclear spectra as well as U, B, Rsurface photometry for a representative sample of 196 nearby galaxies.These galaxies span the entire Hubble sequence in morphological type, aswell as a wide range of luminosities (MB=-14 to -22). Here wepresent the spectrophotometry for these galaxies. The selection of thesample and the U, B, R surface photometry is described in a companionpaper. Our goals for the project include measuring the current starformation rates and metallicities of these galaxies, and elucidatingtheir star formation histories, as a function of luminosity andmorphology. We thereby extend the work of Kennicutt to lower luminositysystems. We anticipate that our study will be useful as a benchmark forstudies of galaxies at high redshift. We describe the observing, datareduction, and calibration techniques and demonstrate that ourspectrophotometry agrees well with that of Kennicutt. The spectra spanthe range 3550-7250 Å at a resolution (FWHM) of ~6 Å andhave an overall relative spectrophotometric accuracy of ~+/-6%. Wepresent a spectrophotometric atlas of integrated and nuclear rest-framespectra as well as tables of equivalent widths and synthetic colors. Theatlas and tables of measurements will be made available electronically.We study the correlations of galaxy properties determined from thespectra and images. Our findings include: (1) galaxies of a givenmorphological class display a wide range of continuum shapes andemission-line strengths if a broad range of luminosities are considered,(2) emission-line strengths tend to increase and continua tend to getbluer as the luminosity decreases, and (3) the scatter on the generalcorrelation between nuclear and integrated Hα emission-linestrengths is large.
|Surface Photometry of Nearby Field Galaxies: The Data|
We have obtained integrated spectra and multifilter photometry for arepresentative sample of ~200 nearby galaxies. These galaxies span theentire Hubble sequence in morphological type, as well as a wide range ofluminosities (MB=-14 to -22) and colors (B-R=0.4-1.8). Herewe describe the sample selection criteria and the U, B, R surfacephotometry for these galaxies. The spectrophotometric results will bepresented in a companion paper. Our goals for the project includemeasuring the current star formation rates and metallicity of thesegalaxies, and elucidating their star formation histories, as a functionof luminosity and morphology. We thereby extend the work of Kennicutt tolower luminosity systems. We anticipate that our study will be useful asa benchmark for studies of galaxies at high redshift. We discuss theobserving, data reduction, and calibration techniques and show that ourphotometry agrees well with previous work in those cases in whichearlier data are available. We present an atlas of images, radialsurface brightness profiles, and color profiles as well as tables ofderived parameters. The atlas and tables of measurements will be madeavailable electronically. We study the correlations of galaxy propertiesdetermined from the galaxy images. Our findings include the following:(1) colors determined within the effective radius correlate better withmorphological type than with MB and (2) 50% of thelow-luminosity galaxies are bluest in their centers.
|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.
|An image database. II. Catalogue between δ=-30deg and δ=70deg.|
A preliminary list of 68.040 galaxies was built from extraction of35.841 digitized images of the Palomar Sky Survey (Paper I). For eachgalaxy, the basic parameters are obtained: coordinates, diameter, axisratio, total magnitude, position angle. On this preliminary list, weapply severe selection rules to get a catalog of 28.000 galaxies, wellidentified and well documented. For each parameter, a comparison is madewith standard measurements. The accuracy of the raw photometricparameters is quite good despite of the simplicity of the method.Without any local correction, the standard error on the total magnitudeis about 0.5 magnitude up to a total magnitude of B_T_=17. Significantsecondary effects are detected concerning the magnitudes: distance toplate center effect and air-mass effect.
|The CfA Redshift Survey: Data for the NGP +36 Zone|
We have assembled redshifts for a complete sample of 719 galaxies withm_zw_ <= 15.5 in the declination range 32.5^deg^ <= δ <=38.5^deg^ and right ascension range 8^h^ <= α <= 17^h^. Wehave determined morphological types for all galaxies in the magnitudelimited sample by direct inspection of the POSS-O plates. 576 of theredshifts are measurements from Mount Hopkins, and 405 are newredshifts. We also include new redshifts for 77 fainter galaxies in thesame strip.
|The far-infrared properties of the CfA galaxy sample. I - The catalog|
IRAS flux densities are presented for all galaxies in the Center forAstrophysics magnitude-limited sample (mB not greater than 14.5)detected in the IRAS Faint Source Survey (FSS), a total of 1544galaxies. The detection rate in the FSS is slightly larger than in thePSC for the long-wavelength 60- and 100-micron bands, but improves by afactor of about 3 or more for the short wavelength 12- and 25-micronbands. This optically selected sample consists of galaxies which are, onaverage, much less IR-active than galaxies in IR-selected samples. Itpossesses accurate and complete redshift, morphological, and magnitudeinformation, along with observations at other wavelengths.
|KISO survey for ultraviolet-excess galaxies. IX|
A set of identification charts is presented for UV-excess galaxiesdetected on multicolor plates for ten survey fields. The charts are partof the Kiso UV galaxy catalog (Takase and Miyauchi-Isobe, 1988). Thisset of charts brings the total number of objects in the catalog to 583,covering a 300-sq deg sky area down to a photographic magnitude of about18. The parameters presented include morphological classifications,image sizes, and degree of UV-excess.
|The Case low-dispersion Northern Sky Survey. V.|
Positions, estimated magnitudes, and finding charts (when necessary) areprovided for 143 blue and/or emission-line galaxies, probable H IIregions in 11 galaxies, 149 blue and/or emission-line stellar objectsincluding QSO candidates, and 36 known and suspected blue stars in theR.A. region between 10 h 10 m and 12 h 15 m and declination between +33.0 and .38.0 deg (1950). The objects, whose blue magnitudes are mostlywithin the range 15-18, were identified on low-dispersionobjective-prism plates taken with the Burrel Schmidt telescope at KittPeak.
|A Study of the Largescale Structure in the Distribution of Galaxies in a Region Centered about the Cancer Cluster - Part Two - Further Observational Results|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986AJ.....91..732B&db_key=AST
|A survey of galaxy redshifts. IV - The data|
The complete list of the best available radial velocities for the 2401galaxies in the merged Zwicky-Nilson catalog brighter than 14.5mz and with b (II) above +40 deg or below -30 deg ispresented. Almost 60 percent of the redshifts are from the CfA surveyand are accurate to typically 35 km/s.
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