A Comparison of Ultraviolet Imaging Telescope Far‐Ultraviolet and Hα Star Formation Rates

2001 ◽  
Vol 548 (2) ◽  
pp. 681-693 ◽  
Author(s):  
Eric F. Bell ◽  
Robert C. Kennicutt, Jr.
Keyword(s):  
Star Formation ◽  
Imaging Telescope ◽  
Far Ultraviolet

scholarly journals The GALEX -VVDS Measurement of the Evolution of the Far-Ultraviolet Luminosity Density and the Cosmic Star Formation Rate

2005 ◽  
Vol 619 (1) ◽  
pp. L47-L50 ◽  
Author(s):  
D. Schiminovich ◽  
O. Ilbert ◽  
S. Arnouts ◽  
B. Milliard ◽  
L. Tresse ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Far Ultraviolet

scholarly journals Ultraviolet Imaging Telescope Observations of the Magellanic Clouds

1999 ◽  
Vol 190 ◽  
pp. 237-238
Author(s):  
Joel Wm. Parker ◽  
Jesse K. Hill ◽  
Robert Cornett ◽  
Joan Hollis ◽  
Emily Zamkoff ◽  
...  
Keyword(s):  
Large Scale ◽  
Massive Star ◽  
Mass Function ◽  
Initial Mass Function ◽  
Wide Field ◽  
Imaging Telescope ◽  
Statistical Studies ◽  
Ob Associations ◽  
Far Ultraviolet ◽  
Range Of Values

We present an analysis of wide-field, far-ultraviolet images of the LMC and SMC obtained by the Ultraviolet Imaging Telescope. The photometric catalog of over 37,000 stars allows us to make large-scale, statistical studies of massive star formation in OB associations and in the field population. Our results show that: (1) the most probable slope for the initial mass function (IMF) of field stars is Γ = −1.80, slightly steeper than the Salpeter slope; and (2) there doesn't seem to be a single, unique IMF slope for stars in OB associations, with a range of values from Γ = −1.0 to −2.0. We also analyze the stellar vs. diffuse UV flux, and the population of OB star candidates in the field.

scholarly journals Standardization in the UV with Astrosat and its issues related to star cluster studies

2018 ◽  
Vol 14 (A30) ◽  
pp. 455-457
Author(s):  
Priya Shah
Keyword(s):  
Data Analysis ◽  
Ultra Violet ◽  
Star Cluster ◽  
The Other ◽  
Space Observatory ◽  
Near Ultraviolet ◽  
Imaging Telescope ◽  
Embedded Clusters ◽  
Far Ultraviolet

AbstractThe Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in Astrosat, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300-1800 Å), and the other for the near-ultraviolet (NUV) channel (2000-3000 Å) and the visible (VIS) channel (3200-5500 Å). We shall discuss the issues with standardization in the UV with reference to Astrosat Observations (Cycle A04). I shall discuss the problems faced in data-analysis and how these in turn lead to serious issues dealing with the color-magnitude diagarms, membership and age of the young embedded clusters studied.

Atlas of Hα images for five hundred nearest dwarf galaxies

2018 ◽  
Vol 14 (S344) ◽  
pp. 283-287
Author(s):  
Serafim S. Kaisin ◽  
Igor D. Karachentsev
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Stellar Mass ◽  
Lenticular Galaxies ◽  
History Of ◽  
Far Ultraviolet

AbstractResults of mass imaging nearby dwarf galaxies in emission Hα line and red continuum with the 6-meter BTA telescope are available via the address: http://www.sao.ru/lv/lvgdb. The sample of dwarfs limited by a distance of 11 Mpc contains about 500 objects. Their Hα - fluxes are used to derive integrated and specific star formation rates of the galaxies. We evaluate the consistency between star formation rates obtained from our Hα-survey and GALEX far-ultraviolet survey. We fix a systematic rise of the ratio SFR(FUV)/SFR(Hα) with the decreasing stellar mass of dwarf galaxies. In the sample there were included only galaxies of late types: T = 10 (Ir), 9 (Im, BCD), 8 (Sdm), 7 (Sd), 6 (Scd), since elliptical and lenticular galaxies, and also spiral with massive bulges, have a significantly different history of star formation.

scholarly journals Calibrating the relation of low-frequency radio continuum to star formation rate at 1 kpc scale with LOFAR

2019 ◽  
Vol 622 ◽  
pp. A8 ◽  
Author(s):  
V. Heesen ◽  
E. Buie II ◽  
C. J. Huff ◽  
L. A. Perez ◽  
J. G. Woolsey ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Low Frequency ◽  
Cosmic Ray ◽  
Radio Continuum ◽  
Gaussian Kernel ◽  
Spatially Resolved ◽  
Sky Survey ◽  
Inverse Compton ◽  
Far Ultraviolet

Context. Radio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free–free) emission. Aims. We calibrate the conversion from the spatially resolved 140 MHz RC emission to the SFR surface density (ΣSFR) at 1 kpc scale. Radio spectral indices give us, by means of spectral ageing, a handle on the transport of cosmic rays using the electrons as a proxy for GeV nuclei. Methods. We used recent observations of three galaxies (NGC 3184, 4736, and 5055) from the LOFAR Two-metre Sky Survey (LoTSS), and archival LOw-Frequency ARray (LOFAR) data of NGC 5194. Maps were created with the facet calibration technique and converted to radio ΣSFR maps using the Condon relation. We compared these maps with hybrid ΣSFR maps from a combination of GALEX far-ultraviolet and Spitzer 24 μm data using plots tracing the relation at the highest angular resolution allowed by our data at 1.2 × 1.2 kpc2 resolution. Results. The RC emission is smoothed with respect to the hybrid ΣSFR owing to the transport of cosmic-ray electrons (CREs) away from star formation sites. This results in a sublinear relation (ΣSFR)RC ∝ [(ΣSFR)hyb]a, where a = 0.59 ± 0.13 (140 MHz) and a = 0.75 ± 0.10 (1365 MHz). Both relations have a scatter of σ = 0.3 dex. If we restrict ourselves to areas of young CREs (α >  −0.65; Iν ∝ να), the relation becomes almost linear at both frequencies with a ≈ 0.9 and a reduced scatter of σ = 0.2 dex. We then simulate the effect of CRE transport by convolving the hybrid ΣSFR maps with a Gaussian kernel until the RC–SFR relation is linearised; CRE transport lengths are l = 1–5 kpc. Solving the CRE diffusion equation, assuming dominance of the synchrotron and inverse-Compton losses, we find diffusion coefficients of D = (0.13–1.5)  × 1028 cm2 s−1 at 1 GeV. Conclusions. A RC–SFR relation at 1.4 GHz can be exploited to measure SFRs at redshift z ≈ 10 using 140 MHz observations.

Implications of Ultraviolet Imaging Telescope observations for star formation histories in NGC 1275

1992 ◽  
Vol 395 ◽  
pp. L49 ◽  
Author(s):  
Eric P. Smith ◽  
Robert W. O'Connell ◽  
Ralph C. Bohlin ◽  
Kwang-Ping Cheng ◽  
Robert H. Cornett ◽  
...  
Keyword(s):  
Star Formation ◽  
Imaging Telescope ◽  
Star Formation Histories ◽  
Ngc 1275

scholarly journals Far-Ultraviolet Observations of Outflows from Infrared-Luminous Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 367-370
Author(s):  
Claus Leitherer ◽  
Rupali Chandar ◽  
Christy A. Tremonti ◽  
Aida Wofford
Keyword(s):  
Star Formation ◽  
Starburst Galaxies ◽  
Metal Enrichment ◽  
Ultraviolet Spectra ◽  
Luminous Galaxies ◽  
Mass Outflow ◽  
Far Ultraviolet ◽  
Ultraviolet Observations

AbstractWe have obtained ultraviolet spectra between 1150 and 1450 Å of four ultraviolet-bright, infrared-luminous starburst galaxies. Our selected sight-lines towards the starburst nuclei probe the conditions in the starburst-driven outflows. We detect outflowing gas with velocities of up to ∼900 km s−1. It is likely that the outflows are a major source of metal enrichment of the galaxies' halos. The mass outflow rates of several tens of M⊙ yr−1 are similar to the star-formation rates. The outflows may quench star formation and ultimately regulate the starburst.

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