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Register a new userThe GALEX View of Supernova Hosts
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We exploit the accumulating, high-quality, multi-wavelength imaging data of nearby supernova (SN) hosts to explore the relationship between SN production and host galaxy evolution. The Galaxy Evolution Explorer (GALEX, Martin et al., 2005) provides ultraviolet (UV) imaging in two bands, complementing data in the optical and infra-red (IR). We compare host properties, derived from spectral energy distribution (SED) fitting, with nearby, well-observed SN Ia light curve properties. We also explore where the hosts of different types of SNe fall relative to the red and blue sequences on the galaxy UV-optical color-magnitude diagram (CMD, Wyder et al., 2007). We conclude that further exploration and larger samples will provide useful results for constraining the progenitors of SNe.
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We present the Pmas/ppak Integral-field Supernova hosts COmpilation (PISCO) which comprises Integral Field Spectroscopy (IFS) of 232 supernova (SN) host galaxies, that hosted 272 SNe, observed over several semesters with the 3.5m telescope at the Calar Alto Observatory (CAHA). PISCO is the largest collection of SN host galaxies observed with wide-field IFS, totaling 466,347 individual spectra covering a typical spatial resolution of $sim$380 pc. While focused studies regarding specific SN Ia- related topics will be published elsewhere, this paper aims to present the properties of the SN environments with stellar population (SP) synthesis and the gas-phase ISM, providing additional results separating stripped-envelope SNe into their subtypes. With 11,270 HII regions detected in all galaxies, we present for the first time an HII region statistical analysis, that puts HII regions that have hosted SNe in context with all other SF clumps within their galaxies. SNe Ic are associated to more metal-rich, higher EW(H{alpha}) and higher SF rate environments within their host galaxies than the mean of all HII regions detected within each host, on contrary SNe IIb occur at the most different environments compared to other CC SNe types. We find two clear components of young and old SP at SNe IIn locations. We find that SNe II fast-decliners (IIL) tend to explode at locations where {Sigma}SFR is more intense. Finally, we outline how a future dedicated IFS survey of galaxies in parallel to an untargeted SN search would overcome the biases in current environmental studies.
The bright galaxy population of the Local Group Analog (LGA) LGG 225 has been imaged with the Galaxy Evolution Explorer (GALEX) through its Far- and Near-UV wavebands. A significant fraction of the group members appear to underwent recent/on-going interaction episodes that strongly disturbed overall galaxy morphology. UV-bright regions, sites of intense star formation activity accompanied by intense dust extinction, mark the galaxy outskirts forming irregular structures and tails. Compared to the Local Group, LGG 225 seems thus to be experiencing a more intense and active evolutionary phase.
(Abridged) Far ultraviolet to far infrared images of the nearby galaxy NGC5194, from Spitzer, GALEX, Hubble Space Telescope and ground--based data, are used to investigate local and global star formation, and the impact of dust extinction in HII-emitting knots. In the IR/UV-UV color plane, the NGC5194 HII knots show the same trend observed for normal star-forming galaxies, having a much larger dispersion than starburst galaxies. We identify the dispersion as due to the UV emission predominantly tracing the evolved, non-ionizing stellar population, up to ages 50-100 Myr. While in starbursts the UV light traces the current SFR, in NGC5194 it traces a combination of current and recent-past SFR. Unlike the UV emission, the monochromatic 24 micron luminosity is an accurate local SFR tracer for the HII knots in NGC5194; this suggests that the 24 micron emission carriers are mainly heated by the young, ionizing stars. However, preliminary results show that the ratio of the 24 micron emission to the SFR varies by a factor of a few from galaxy to galaxy. While also correlated with star formation, the 8 micron emission is not directly proportional to the number of ionizing photons. This confirms earlier suggestions that the carriers of the 8 micron emission are heated by more than one mechanism.
SN 1572 (Tycho Brahes supernova) clearly belongs to the Ia (thermonuclear) type. It was produced by the explosion of a white dwarf in a binary system. Its remnant has been the first of this type to be explored in search of a possible surviving companion, the mass donor that brought the white dwarf to the point of explosion. A high peculiar motion with respect to the stars at the same location in the Galaxy, mainly due to the orbital velocity at the time of the explosion, is a basic criterion for the detection of such companions. Radial velocities from the spectra of the stars close to the geometrical center of Tychos supernova remnant, plus proper motions of the same stars, obtained by astrometry with the {it Hubble Space Telescope}, have been used so far. In addition, a detailed chemical analysis of the atmospheres of a sample of candidate stars had been made. However, the distances to the stars, remained uncertain. Now, the Second {it Gaia} Data Release (DR2) provides unprecedent accurate distances and new proper motions for the stars can be compared with those made from the {it HST}. We consider the Galactic orbits that the candidate stars to SN companion would have in the future. We do this to explore kinematic peculiarity. We also locate a representative sample of candidate stars in the Toomre diagram. Using the new data, we reevaluate here the status of the candidates suggested thus far, as well as the larger sample of the stars seen in the central region of the remnant.
We study the two galaxies NGC4621 and NGC4374 in the Virgo cluster to derive their distances and stellar population properties. The targets have hosted three type Ia Supernova events allowing to investigate the correlations between the SNeIa and their host stellar systems. Using deep BVR data, obtained with FORS2 at the VLT, we analyse the Surface Brightness Fluctuations (SBF) properties of the targets. We adopt our measurements and existing calibrations to estimate the distance of NGC4621 and NGC4374. For stellar population analysis, we measured SBF amplitudes in different galaxy regions. We present a detailed comparison between data and models to constrain the characteristics of the dominant stellar components at i) various galactic radii, and ii) in the regions where SNeIa were recorded. Our V and R SBF measures provide distances in agreement with literature estimates. The median of our and literature SBF-based distances agrees with the one from non-SBF methods. Comparing data with models we find that stellar populations properties do not change significantly along galactic radius, with a dominant population having old age and solar chemical composition. The galaxies appear similar in all properties analysed, except for B-band SBF. Since the SBF magnitudes in this band are sensitive to the properties of a hot stellar component, we speculate that such behaviour is a consequence of different diffuse hot components in the galaxies. We find that the presence of a percentage of hot-HB stars in old and metal rich stellar populations could be at the origin of the observed differences. We find a good uniformity in the V and R SBF and integrated colours in the regions where the three SNeIa exploded. On the other hand, the B-band SBF signal shows intriguing differences.
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