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The H? luminosity function and star formation rate up to z ~ 1
We describe ISAAC/ESO-VLT observations of the H??6563Balmer line of 33 field galaxies from the Canada-France Redshift Survey(CFRS) with redshifts selected between 0.5 and 1.1. We detect H?in emission in 30 galaxies and compare the properties of this samplewith the low-redshift sample of CFRS galaxies at z~ 0.2. We find thatthe H? luminosity, L(H?), is tightly correlated toM(BAB) in the same way for both the low- and high-redshiftsamples. L(H?) is also correlated to L([OII]?3727), andagain the relation appears to be similar at low and high redshifts. Theratio L(lsqbOII])/L(H?) decreases for brighter galaxies by as muchas a factor of 2 on average. Derived from the H? luminosityfunction, the comoving H? luminosity density increases by a factor12 from = 0.2 to = 1.3. Our results confirm a strongrise of the star formation rate (SFR) at z < 1.3, proportional to (1+z)4.1+/-0.3 (with H0= 50 km s-1Mpc-1, q0= 0.5). We find an average SFR(2800Å)/SFR (H?) ratio of 3.2 using the Kennicutt SFRtransformations. This corresponds to the dust correction that isrequired to make the near-ultraviolet data consistent with thereddening-corrected H? data within the self-contained, I-selectedCFRS sample.
| The Giant Radio Galaxy MRC B0319-454: Circumnuclear Structure of the Host Galaxy ESO 248-G10
We present optical and near-infrared images and spectra of ESO 248-G10,the host of the giant radio galaxy MRC B0319-454. From near-infraredcolors, the active nucleus is shown to be reddened by hot dust emissionor dust extinction. Star-forming regions are identified beyond a radiusof 5" (8.1 kpc) where hot gas is prevalent. The optical spectrum showsgas rotation at speeds of up to ~350 km s-1 out to >=32kpc along the radio axis. A model is proposed in which the giantelliptical is triaxial with the radio axis along the short axis, and thefigure rotation is around the long axis. From the model, the angles ofthe principal axis are ψ=34deg,θ=65deg, and φ=19deg with axis ratiosof B/A=0.75 and C/A=0.69. A second velocity feature from 5" to 15" tothe northeast of the nucleus is proposed to be a merging gas-rich galaxyinducing star formation while settling into an orbit about the figurerotation axis.
| Infrared Photometry of Red Supergiants in Young Clusters in the Magellanic Clouds
We present broadband infrared photometry for 52 late-type supergiants inthe young Magellanic Cloud clusters NGC 330, 1818, 2004, and 2100.Standard models are seen to differ in the temperature they predict forthe red supergiant population by on the order of 300 K. It appears thatthese differences are most probably due to the calibration of themixing-length parameter alpha_P in the outermost layers of the stellarenvelope. Because alpha_P apparently depends on the model used, we donot quantitatively compare alpha_P between models. Qualitatively, wefind that alpha_P decreases with increased stellar mass within standardmodels. We do not find evidence that alpha_P depends on metallicity.
| Fainter Southern JHK Standards Suitable for Infrared Arrays
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995MNRAS.276..734C&db_key=AST
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| Takýmyýldýz: | Irmak |
| Sað Açýklýk: | 03h13m25.70s |
| Yükselim: | -43°21'55.5" |
| Görünürdeki Parlaklýk: | 9.311 |
| özdevim Sað Açýklýk: | 23.7 |
| özdevim Yükselim: | 14.2 |
| B-T magnitude: | 9.7 |
| V-T magnitude: | 9.344 |
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