scholarly journals The beauty of resolution: The SN Ib factory NGC 2770 spatially resolved

2014 ◽  
Vol 10 (S309) ◽  
pp. 169-170
Author(s):  
C. C. Thöne ◽  
L. Christensen ◽  
J. Gorosabel ◽  
A. de Ugarte Postigo
Keyword(s):  
Stellar Population ◽  
Late Type ◽  
Spiral Arms ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
The Galaxy ◽  
History Of ◽  
First Time

AbstractThe late-type spiral NGC 2770 hosted 3 Type Ib supernovae (SNe) in or next to star-forming regions in its outer spiral arms. We study the properties of the SN sites and the galaxy at different spatial resolutions to infer propeties of the SN progenitors and the SF history of the galaxy. Several 3D techniques are used and, for the first time, we present images of metallicity, shocks and stellar population ages from OSIRIS/GTC imaging with tunable narrowband filters.

scholarly journals Using stellar population studies to determine the progenitors of GRBs and SNe

2009 ◽  
Vol 5 (S262) ◽  
pp. 436-437
Author(s):  
Christina C. Thöne ◽  
Lise Christensen ◽  
Johan P. U. Fynbo
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Population Studies ◽  
Population Models ◽  
Host Galaxy ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions

AbstractWe present spatially resolved emission line studies of three nearby GRB and SN hosts with longslit and/or IFU observations. We compare the environment of the GRBs/SNe with those of other star-forming regions in the host galaxy and try to get informations on the progenitor from stellar population models and metallicities.

scholarly journals RadioAstron space-VLBI project: studies of masers in star forming regions of our Galaxy and megamasers in external galaxies

2017 ◽  
Vol 13 (S336) ◽  
pp. 417-421 ◽  
Author(s):  
A. M. Sobolev ◽  
N. N. Shakhvorostova ◽  
A. V. Alakoz ◽  
W. A. Baan
Keyword(s):  
Angular Resolution ◽  
Nearby Galaxy ◽  
Major Step ◽  
Maser Emission ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
External Galaxies ◽  
First Time ◽  
Water Maser

AbstractObservations of the masers in the course of RadioAstron mission yielded detections of fringes for a number of sources in both water and hydroxyl maser transitions. Several sources display numerous ultra-compact details. This proves that implementation of the space VLBI technique for maser studies is possible technically and is not always prevented by the interstellar scattering, maser beaming and other effects related to formation, transfer, and detection of the cosmic maser emission. For the first time, cosmic water maser emission was detected with projected baselines exceeding Earth Diameter. It was detected in a number of star-forming regions in the Galaxy and two megamaser galaxies NGC 4258 and NGC 3079. RadioAstron observations provided the absolute record of the angular resolution in astronomy. Fringes from the NGC 4258 megamaser were detected on baseline exceeding 25 Earth Diameters. This means that the angular resolution sufficient to measure the parallax of the water maser source in the nearby galaxy LMC was directly achieved in the cosmic maser observations. Very compact features with angular sizes about 20\muas\, have been detected in star-forming regions of our Galaxy. Corresponding linear sizes are about 5-10 million kilometers. So, the major step from milli- to micro-arcsecond resolution in maser studies is achieved by the RadioAstron mission. The existence of the features with extremely small angular sizes is established. Further implementations of the space–VLBI maser instrument for studies of the nature of cosmic objects, studies of the interaction of extremely high radiation field with molecular material and studies of the matter on the line of sight are planned.

scholarly journals History of the solar environment

2008 ◽  
Vol 4 (S257) ◽  
pp. 465-470
Author(s):  
Kurt Marti ◽  
Bernard Lavielle
Keyword(s):  
Time Scales ◽  
Decay Product ◽  
Galactic Cosmic Rays ◽  
Solar Neighborhood ◽  
Iron Meteorites ◽  
Spiral Arms ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
Flux Increase

AbstractGalactic cosmic rays (GCR) provide information on the solar neighborhood during the sun's motion in the galaxy. There is now considerable evidence for GCR acceleration by shock waves of supernova in active star-forming regions (OB associations) in the galactic spiral arms. During times of passage into star-forming regions increases in the GCR-flux are expected. Recent data from the Spitzer Space Telescope (SST) are shedding light on the structure of the Milky Way and of its star-forming-regions in spiral arms. Records of flux variations may be found in solar system detectors, and iron meteorites with GCR-exposure times of several hundred million years have long been considered to be potential detectors (Voshage, 1962). Variable concentration ratios of GCR-produced stable and radioactive nuclides, with varying half-lives and therefore integration times, were reported by Lavielleet al. (1999), indicating a recent 38% GCR-flux increase. Potential flux recorders consisting of different pairs of nuclides can measure average fluxes over different time scales (Lavielleet al., 2007; Mathew and Marti, 2008). Specific characteristics of two pairs of recorders (81Kr-Kr and129I-129Xe) are the properties of self-correction for GCR-shielding (flux variability within meteorites of varying sizes). The81Kr-Kr method (Marti, 1967) is based on Kr isotope ratios, while stable129Xe is the decay product of the radionuclide129I, which is produced by secondary neutron reactions on Te in troilites of iron meteorites. The two chronometers provide records of the average GCR flux over 1 and 100 million year time scales, respectively.

scholarly journals Early galaxy growth: mergers or gravitational instability?

2020 ◽  
Vol 500 (1) ◽  
pp. 118-137
Author(s):  
A Zanella ◽  
A Pallottini ◽  
A Ferrara ◽  
S Gallerani ◽  
S Carniani ◽  
...  
Keyword(s):  
Gravitational Instability ◽  
Far Infrared ◽  
Joint Effect ◽  
Data Sets ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
James Webb Space Telescope ◽  
The Galaxy ◽  
Hydrodynamical Simulations

ABSTRACT We investigate the spatially resolved morphology of galaxies in the early Universe. We consider a typical redshift z = 6 Lyman break galaxy, ‘Althæa’, from the SERRA hydrodynamical simulations. We create mock rest-frame ultraviolet (UV), optical, and far-infrared observations, and perform a two-dimensional morphological analysis to deblend the galaxy disc from substructures (merging satellites or star-forming regions). We find that the [C ii]158 μm emitting region has an effective radius 1.5–2.5 times larger than the optical one, consistent with recent observations. This [C ii] halo in our simulated galaxy arises as the joint effect of stellar outflows and carbon photoionization by the galaxy UV field, rather than from the emission of unresolved nearby satellites. At the typical angular resolution of current observations (≳ 0.15 arcsec) only merging satellites can be detected; detection of star-forming regions requires resolutions of ≲ 0.05 arcsec. The [C ii]-detected satellite has a 2.5-kpc projected distance from the galaxy disc, whereas the star-forming regions are embedded in the disc itself (distance ≲ 1 kpc). This suggests that multicomponent systems reported in the literature, which have separations ≳ 2 kpc, are merging satellites, rather than galactic substructures. Finally, the star-forming regions found in our mock maps follow the local L[C ii]–SFRUV relation of galaxy discs, although sampling the low-luminosity, low-SFR tail of the distribution. We show that future James Webb Space Telescope observations, bridging UV and [C ii] data sets, will be exceptionally suited to characterize galaxy substructures, thanks to their exquisite spatial resolution and sensitivity to both low-metallicity and dust-obscured regions that are bright at infrared wavelengths.

scholarly journals Spatial regularity of the young stellar population in the ring of NGC 6217

2020 ◽  
Vol 640 ◽  
pp. L7
Author(s):  
Alexander S. Gusev ◽  
Elena V. Shimanovskaya
Keyword(s):  
Stellar Population ◽  
Temporal Distribution ◽  
Extensive Study ◽  
Good Test ◽  
Spiral Arms ◽  
Star Forming ◽  
Relative Contribution ◽  
The Galaxy ◽  
Spatial Regularity ◽  
Ring Structures

The relative contribution of various physical processes to the spatial and temporal distribution of molecular clouds and star-forming regions in the disks of galaxies has not yet been the subject of extensive study. Investigating the spatial regularity in the distribution of the young stellar population in spiral and ring structures is a good test for studying this contribution. In this paper, we look at the photometric properties of the ring and spiral arms in the barred spiral galaxy NGC 6217 based on an analysis using GALEX ultraviolet, optical UBVRI, and Hα surface photometry data. The ring in the galaxy is located near the corotation area. We found evidence of spatial regularity in the distribution of the young stellar population along the galaxy ring. The characteristic scale of spacing is about 700 pc. At the same time, we did not find a similar regularity in the distribution of the young stellar population along the spiral arms of NGC 6217. The spatial regularity in the concentration of young stellar groupings along spiral arms is a quite rare phenomenon and it has never previously been seen in galactic rings.

scholarly journals Maser astrometry with VERA and Galactic structure

2012 ◽  
Vol 8 (S287) ◽  
pp. 386-390 ◽  
Author(s):  
Mareki Honma ◽  
Takumi Nagayama ◽  
Tomoya Hirota ◽  
Naoko Matsumoto ◽  
Nobuyuki Sakai ◽  
...  
Keyword(s):  
Rotation Curve ◽  
Galactic Structure ◽  
Proper Motions ◽  
Late Type ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
Maser Sources

AbstractSince 2007 VERA (VLBI Exploration of Radio Astrometry) has been producing astrometric results (distances and/or proper motions) for Galactic maser sources. Nearly 30 parallaxes have been obtained for star-forming regions and late-type stars. By using VERA's astrometric results for star-forming regions, combined with those obtained with VLBA and EVN, fundamental Galactic parameters and Galactic structure may be derived. Our results show that R0 = 8.4 ± 0.4 kpc and Ω⊙ ≡ Ω0 + V⊙/R0=30.7±0.8 km s−1 kpc−1, and also show that the rotation curve of the Galaxy is nearly flat. The determinations of Galactic parameters and structures demonstrate that the maser astrometry can not only contribute significantly to research of individual maser sources, but also to studies of the structure of the Galaxy.

scholarly journals Spatially resolved properties of supernova host galaxies in SDSS-IV MaNGA

2022 ◽  
Vol 21 (12) ◽  
pp. 306
Author(s):  
Hong-Xuan Zhang ◽  
Yan-Mei Chen ◽  
Yong Shi ◽  
Min Bao ◽  
Xiao-Ling Yu
Keyword(s):  
Stellar Population ◽  
Velocity Dispersion ◽  
Control Sample ◽  
Stellar Mass ◽  
Host Galaxies ◽  
Star Forming ◽  
Spatially Resolved ◽  
The Galaxy ◽  
Type Ia ◽  
Natural Result

Abstract We crossmatch galaxies from Mapping Nearby Galaxies at Apache Point Observatory with the Open Supernova Catalog, obtaining a total of 132 SNe within MaNGA bundle. These 132 SNe can be classified into 67 Type Ia and 65 Type CC. We study the global and local properties of supernova host galaxies statistically. Type Ia SNe are distributed in both star-forming galaxies and quiescent galaxies, while Type CC SNe are all distributed along the star-forming main sequence. As the stellar mass increases, the Type Ia/CC number ratio increases. We find: (1) there is no obvious difference in the interaction possibilities and environments between Type Ia SN hosts and a control sample of galaxies with similar stellar mass and SFR distributions, except that Type Ia SNe tend to appear in galaxies which are more bulge-dominated than their controls. For Type CC SNe, there is no difference between their hosts and the control galaxies in galaxy morphology, interaction possibilities as well as environments; (2) compared to galaxy centers, the SN locations have smaller velocity dispersion, lower metallicity, and younger stellar population. This is a natural result of radius gradients for all these parameters. The SN location and its symmetrical position relative to the galaxy center, as well as regions with similar effective radii have very similar [Mg/Fe], gas-phase metallicity, gas velocity dispersion and stellar population age.

scholarly journals PÉGASE.3: A code for modeling the UV-to-IR/submm spectral and chemical evolution of galaxies with dust

2019 ◽  
Vol 623 ◽  
pp. A143 ◽  
Author(s):  
Michel Fioc ◽  
Brigitte Rocca-Volmerange
Keyword(s):  
Near Infrared ◽  
Far Infrared ◽  
Spectral Energy ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
History Of ◽  
Mass Assembly ◽  
Individual Grains ◽  
The Masses

A code computing consistently the evolution of stars, gas and dust, as well as the energy they radiate, is required to derive reliably the history of galaxies by fitting synthetic spectral energy distributions (SEDs) to multiwavelength observations. The new code PÉGASE.3 described in this paper extends to the far-infrared/submillimeter the ultraviolet-to-near-infrared modeling provided by previous versions of PÉGASE. It first computes the properties of single stellar populations at various metallicities. It then follows the evolution of the stellar light of a galaxy and the abundances of the main metals in the interstellar medium (ISM), assuming some scenario of mass assembly and star formation. It simultaneously calculates the masses of the various grain families, the optical depth of the galaxy and the attenuation of the SED through the diffuse ISM in spiral and spheroidal galaxies, using grids of radiative transfer precomputed with Monte Carlo simulations taking scattering into account. The code determines the mean radiation field and the temperature probability distribution of stochastically heated individual grains. It then sums up their spectra to yield the overall emission by dust in the diffuse ISM. The nebular emission of the galaxy is also computed, and a simple modeling of the effects of dust on the SED of star-forming regions is implemented. The main outputs are ultraviolet-to-submillimeter SEDs of galaxies from their birth up to 20 Gyr, colors, masses of galactic components, ISM abundances of metallic elements and dust species, supernova rates. The temperatures and spectra of individual grains are also available. The paper discusses several of these outputs for a scenario representative of Milky Way-like spirals. PÉGASE.3 is fully documented and its Fortran 95 source files are public. The code should be especially useful for cosmological simulations and to interpret future mid- and far-infrared data, whether obtained by JWST, LSST, Euclid or e-ELT.

scholarly journals A revised estimate of the distance to the clouds in the Chamaeleon complex using the Tycho–Gaia Astrometric Solution

2018 ◽  
Vol 610 ◽  
pp. A64 ◽  
Author(s):  
Jordan Voirin ◽  
Carlo F. Manara ◽  
Timo Prusti
Keyword(s):  
Large Scale ◽  
Galactic Plane ◽  
Stellar Content ◽  
Nearby Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Systematic Uncertainties ◽  
The Galaxy ◽  
Color Excess ◽  
First Time

Context. The determination of the distance to dark star-forming clouds is a key parameter to derive the properties of the cloud itself and of its stellar content. This parameter is still loosely constrained even in nearby star-forming regions. Aim. We want to determine the distances to the clouds in the Chamaeleon-Musca complex and explore the connection between these clouds and the large-scale cloud structures in the Galaxy. Methods. We used the newly estimated distances obtained from the parallaxes measured by the Gaia satellite and included in the Tycho–Gaia Astrometric Solution catalog. When known members of a region are included in this catalog we used their distances to infer the distance to the cloud. Otherwise, we analyzed the dependence of the color excess on the distance of the stars and looked for a turn-on of this excess, which is a proxy of the position of the front-edge of the star-forming cloud. Results. We are able to measure the distance to the three Chamaeleon clouds. The distance to Chamaeleon I is 179-10-10+11+11pc, where the quoted uncertainties are statistical and systematic uncertainties, respectively, ~20 pc further away than previously assumed. The Chamaeleon II cloud is located at the distance of 181-5-10+6+11pc, which agrees with previous estimates. We are able to measure for the first time a distance to the Chamaeleon III cloud of 199-7-11+8+12pc. Finally, the distance of the Musca cloud is smaller than 603603-70-92+91+133 pc. These estimates do not allow us to distinguish between the possibility that the Chamaeleon clouds are part of a sheet of clouds parallel to the Galactic plane, or perpendicular to it. Conclusions. We measured a larger distance to the Chamaeleon I cloud than assumed in the past, confirmed the distance to the Chamaeleon II region, and measured for the first time the distance to the Chamaleon III cloud. These values are consistent with the scenario in which the three clouds are part of a single large-scale structure. Gaia Data Release 2 will allow us to put more stringent constraints on the distances to these clouds by giving us access to parallax measurements for a larger number of members of these regions.

scholarly journals Discovery of a 21 Myr old stellar population in the Orion complex

2019 ◽  
Vol 631 ◽  
pp. A166 ◽  
Author(s):  
Janez Kos ◽  
Joss Bland-Hawthorn ◽  
Martin Asplund ◽  
Sven Buder ◽  
Geraint F. Lewis ◽  
...  
Keyword(s):  
Stellar Population ◽  
Orion Nebula ◽  
Proper Motions ◽  
Dimensional Parameter ◽  
Star Forming ◽  
Formation History ◽  
The Galaxy ◽  
History Of ◽  
The Impact ◽  
Stellar Aggregate

Context. The Orion complex is arguably the most studied star-forming region in the Galaxy. While stars are still being born in the Orion nebula, the oldest part was believed to be no more than 13 Myr old. Aims. In order to study the full hierarchy of star formation across the Orion complex, we perform a clustering analysis of the Ori OB1a region using new stellar surveys and derive robust ages for each identified stellar aggregate. Methods. We use Gaia DR2 parameters supplemented with radial velocities from the GALAH and APOGEE surveys to perform clustering of the Ori OB1a association. Five overdensities are resolved in a six-dimensional parameter space (positions, distance, proper motions, and radial velocity). Most correspond to previously known structures (ASCC 16, 25 Orionis, ASCC 20, ASCC 21). We use Gaia DR2, Pan-STARRS1 and 2MASS photometry to fit isochrones to the colour-magnitude diagrams of the identified clusters. The ages of the clusters can thus be measured with ∼10% precision. Results. While four of the clusters have ages between 11 and 13 Myr, the ASCC 20 cluster stands out at an age of 21 ± 3 Myr. This is significantly greater than the age of any previously known component of the Orion complex. To some degree, all clusters overlap in at least one of the six phase-space dimensions. Conclusions. We argue that the formation history of the Orion complex, and its relation to the Gould belt, must be reconsidered. A significant challenge in reconstructing the history of the Ori OB1a association is to understand the impact of the newly discovered 21 Myr old population on the younger parts of the complex, including their formation.

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