- ID:
- ivo://CDS.VizieR/J/AJ/155/234
- Title:
- Star formation rate distribution in NGC 1232
- Short Name:
- J/AJ/155/234
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- NGC 1232 is a face-on spiral galaxy and a great laboratory for the study of star formation due to its proximity. We obtained high spatial resolution H{alpha} images of this galaxy, with adaptive optics, using the SAM instrument at the SOAR telescope, and used these images to study its H II regions. These observations allowed us to produce the most complete H II region catalog for it to date, with a total of 976 sources. This doubles the number of H II regions previously found for this object. We used these data to construct the H II luminosity function, and obtained a power-law index lower than the typical values found for Sc galaxies. This shallower slope is related to the presence of a significant number of high-luminosity H II regions (log L>39 dex). We also constructed the size distribution function, verifying that, as for most galaxies, NGC 1232 follows an exponential law. We also used the H{alpha} luminosity to calculate the star formation rate. An extremely interesting fact about this galaxy is that X-ray diffuse observations suggest that NGC 1232 recently suffered a collision with a dwarf galaxy. We found an absence of star formation around the region where the X-ray emission is more intense, which we interpret as a star formation quenching due to the collision. Along with that, we found an excess of star-forming regions in the northeast part of the galaxy, where the X-ray emission is less intense.
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Search Results
- ID:
- ivo://CDS.VizieR/J/PASP/123/1011
- Title:
- Star Formation Reference Survey (SFRS)
- Short Name:
- J/PASP/123/1011
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Star formation is arguably the most important physical process in the cosmos. It is a fundamental driver of galaxy evolution and the ultimate source of most of the energy emitted by galaxies. A correct interpretation of star formation rate (SFR) measures is therefore essential to our understanding of galaxy formation and evolution. Unfortunately, however, no single SFR estimator is universally available or even applicable in all circumstances: the numerous galaxies found in deep surveys are often too faint (or too distant) to yield significant detections with most standard SFR measures, and until now there have been no global, multi-band observations of nearby galaxies that span all the conditions under which star-formation is taking place. To address this need in a systematic way, we have undertaken a multi-band survey of all types of star-forming galaxies in the local Universe. This project, the Star Formation Reference Survey (SFRS), is based on a statistically valid sample of 369 nearby galaxies that span all existing combinations of dust temperature, SFR, and specific SFR. Furthermore, because the SFRS is blind with respect to AGN fraction and environment it serves as a means to assess the influence of these factors on SFR. Our panchromatic global flux measurements (including GALEX FUV+NUV, SDSS ugriz, 2MASS JHKs, Spitzer 3-8um, and others) furnish uniform SFR measures and the context in which their reliability can be assessed. This paper describes the SFRS survey strategy, defines the sample, and presents the multi-band photometry collected to date.
- ID:
- ivo://CDS.VizieR/J/A+A/430/941
- Title:
- Star formation region NGC 6530
- Short Name:
- J/A+A/430/941
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present astrometry and BVI photometry, down to V~22, of the very young open cluster NGC 6530, obtained from observations taken with the Wide Field Imager camera at the MPG/ESO 2.2m Telescope. We have positionally matched our optical catalog with the list of X-ray sources found in a Chandra-ACIS observation, finding a total of 828 common stars, 90% of which are pre-main sequence stars in NGC 6530.
- ID:
- ivo://CDS.VizieR/J/AJ/138/1203
- Title:
- Star formation regions in nearby dwarf galaxies
- Short Name:
- J/AJ/138/1203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare star formation in the inner and outer disks of 11 dwarf irregular galaxies (dIm) within 3.6Mpc. The regions are identified on Galaxy Evolution Explorer near-UV images, and modeled with UV, optical, and near-IR colors to determine masses and ages. A few galaxies have made 10^5^-10^6^M_{sun}_ complexes in a starburst phase, while others have not formed clusters in the last 50Myr. The maximum region mass correlates with the number of regions as expected from the size-of-sample effect. We find no radial gradients in region masses and ages, even beyond the realm of H{alpha} emission, although there is an exponential decrease in the luminosity density and number density of the regions with radius. H{alpha} is apparently lacking in the outer parts only because nebular emission around massive stars is too faint to see. The outermost regions for the five galaxies with HI data formed at average gas surface densities of 1.9-5.9M_{sun}/pc^2^.
- ID:
- ivo://CDS.VizieR/J/AZh/88/342
- Title:
- Star-forming regions in NGC 5585 and IC 1525
- Short Name:
- J/AZh/88/342
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use UBVRI CCD photometry to study star-forming regions (SFRs) in the galaxies NGC 5585 and IC 1525. The observations were acquired with the 1.5-m telescope of the Mt. Maidanak Observatory of the Astronomical Institute of the Uzbek Academy of Sciences (Uzbekistan), with seeing of 0.8"-1.8". We identified 47 SFRs in NGC 5585 and 16 SFRs in IC 1525.
- ID:
- ivo://CDS.VizieR/J/ApJ/730/88
- Title:
- Star-forming regions in NGC 6822 from UV data
- Short Name:
- J/ApJ/730/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We characterize the star formation in the low-metallicity galaxy NGC 6822 over the past few hundred million years, using GALEX far-UV (FUV, 1344-1786{AA}) and near-UV (NUV, 1771-2831{AA}) imaging, and ground-based H{alpha} imaging. From the GALEX FUV image, we define 77 star-forming (SF) regions with area >860pc^2^, and surface brightness <~26.8 mag (AB) arcsec^-2^, within 0.2{deg} (1.7kpc) of the center of the galaxy. We estimate the extinction by interstellar dust in each SF region from resolved photometry of the hot stars it contains: E(B-V) ranges from the minimum foreground value of 0.22mag up to 0.66+/-0.21mag. The integrated FUV and NUV photometry, compared with stellar population models, yields ages of the SF complexes up to a few hundred Myr, and masses from 2x10^2^M_{sun}_ to 1.5x10^6^M_{sun}_. The derived ages and masses strongly depend on the assumed type of interstellar selective extinction, which we find to vary across the galaxy. The total mass of the FUV-defined SF regions translates into an average star formation rate (SFR) of 1.4x10^-2^M_{sun}_/yr over the past 100Myr, and SFR=1.0x10^-2^M_{sun}_/yr in the most recent 10Myr. The latter is in agreement with the value that we derive from the H{alpha} luminosity, SFR=0.008M_{sun}_/yr. The SFR in the most recent epoch becomes higher if we add the SFR=0.02M_{sun}_/yr inferred from far-IR measurements, which trace star formation still embedded in dust (age <~ a few Myr).
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/3393
- Title:
- Stars and globulars in NGC4494
- Short Name:
- J/MNRAS/415/3393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive analysis of the spatial, kinematic and chemical properties of stars and globular clusters (GCs) in the 'ordinary' elliptical galaxy NGC 4494 using data from the Keck and Subaru telescopes. We derive galaxy surface brightness and colour profiles out to large galactocentric radii. We compare the latter to metallicities derived using the near-infrared Calcium Triplet. We obtain stellar kinematics out to ~3.5 effective radii.
- ID:
- ivo://CDS.VizieR/J/A+A/521/A61
- Title:
- Stars associated to Eagle Nebula (M16=NGC6611)
- Short Name:
- J/A+A/521/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive star-forming regions are characterized by intense ionizing fluxes, strong stellar winds and, occasionally, supernovae explosions, all of which have important effects on the surrounding media, on the star-formation process and on the evolution of young stars and their circumstellar disks. We present a multiband study of the massive young cluster NGC 6611 and its parental cloud (the Eagle Nebula) with the aim of studying how OB stars affect the early stellar evolution and the formation of other stars. We search for evidence of triggering of star formation by the massive stars inside NGC 6611 on a large spatial scale (~10 parsec) and ongoing disk photoevaporation in NGC 6611 and how its efficiency depends on the mass of the central stars.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2677
- Title:
- Stars in the Carina dSph galaxy field
- Short Name:
- J/AJ/130/2677
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The question of the existence of active and prominent tidal disruption around various Galactic dwarf spheroidal (dSph) galaxies remains controversial. That debate often centers on the nature (bound vs. unbound) of extended populations of stars claimed to lie outside the bounds of single King profiles fitted to the density distributions of dSph centers. However, the more fundamental issue of the very existence of the previously reported extended populations is still contentious. We present a critical evaluation of the debate centering on one particular dSph, Carina, for which claims both for and against the existence of stars beyond the King limiting radius have been made.
- ID:
- ivo://CDS.VizieR/J/A+A/272/235
- Title:
- Stars in the dark cloud L1251
- Short Name:
- J/A+A/272/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distance of the dark cloud L1251 was estimated from observations made at the Konkoly Observatory between 1985 and 1991. The spectral classification and the H{alpha} emission features were measured on objective-prism plates taken with the 60/80/180 Schmidt telescope; the photometry was derived from observations made on photographic plates with emulsion-filter combinations giving magnitudes in the Johnson photometric system. The distance of the cloud was found to be 300+/-50pc.
