We present a statistical analysis of the environments of 11 supernovae (SNe) which occurred in six nearby galaxies (z ≲ 0.016). All galaxies were observed with MUSE, the high spatial resolution ...integral-field spectrograph mounted to the 8 m VLT UT4. These data enable us to map the full spatial extent of host galaxies up to ∼3 effective radii. In this way, not only can one characterize the specific host environment of each SN, one can compare their properties with stellar populations within the full range of other environments within the host. We present a method that consists of selecting all H ii regions found within host galaxies from 2D extinction-corrected Hα emission maps. These regions are then characterized in terms of their Hα equivalent widths, star formation rates and oxygen abundances. Identifying H ii regions spatially coincident with SN explosion sites, we are thus able to determine where within the distributions of host galaxy e.g. metallicities and ages each SN is found, thus providing new constraints on SN progenitor properties. This initial pilot study using MUSE opens the way for a revolution in SN environment studies where we are now able to study multiple environment SN progenitor dependencies using a single instrument and single pointing.
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 3.5 m 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 ∼380 pc. Focused studies regarding specific SN Ia-related topics will be published elsewhere; this paper aims to present the properties of the SN environments, using stellar population (SP) synthesis, and the gas-phase interstellar medium, providing additional results separating stripped-envelope SNe into their subtypes. With 11,270 H ii regions detected in all galaxies, we present for the first time a statistical analysis of H ii regions, which puts H ii regions that have hosted SNe in context with all other star-forming clumps within their galaxies. SNe Ic are associated with environments that are more metal-rich and have higher EW(H ) and higher star formation rate within their host galaxies than the mean of all H ii regions detected within each host. This in contrast to SNe IIb, which occur in environments that are very different compared to other core-collapse SNe types. We find two clear components of young and old SPs at SNe IIn locations. We find that SNe II fast decliners tend to explode at locations where the 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.
PINGS: the PPAK IFS Nearby Galaxies Survey Rosales-Ortega, F. F.; Kennicutt, R. C.; Sánchez, S. F. ...
Monthly notices of the Royal Astronomical Society,
06/2010, Volume:
405, Issue:
2
Journal Article
Peer reviewed
Open access
We present the PPAK Integral Field Spectroscopy (IFS) Nearby Galaxies Survey (PINGS), a two-dimensional spectroscopic mosaicking of 17 nearby disc galaxies in the optical wavelength range. This ...project represents the first attempt to obtain continuous coverage spectra of the whole surface of a galaxy in the nearby Universe. The final data set comprises more than 50 000 individual spectra, covering in total an observed area of nearly 80 arcmin2. The observations will be supplemented with broad-band and narrow-band imaging for those objects without publicly available images in order to maximize the scientific and archival values of the data set. In this paper we describe the main astrophysical issues to be addressed by the PINGS project, present the galaxy sample and explain the observing strategy, the data reduction process and all uncertainties involved. Additionally, we give some scientific highlights extracted from the first analysis of the PINGS sample. A companion paper will report on the first results obtained for NGC 628: the largest IFS survey on a single galaxy.
ABSTRACT
We explore the effects of tidal interactions on star formation (SF) by analysing a sample of CALIFA survey galaxies. The sample consists of tidally and non-tidally perturbed galaxies whose ...star-forming regions are paired at the closest stellar mass surface densities, even between the same galaxy types. The regions are then compared, both on the resolved star-formation main sequence (SFMS) plane and in annular property profiles. Star-forming regions in tidally perturbed galaxies exhibit flatter SFMS slopes compared to star-forming regions in non-tidally perturbed galaxies. Despite the fact that the annular profiles show star-forming regions in tidally perturbed galaxies as being mostly older, their SF properties are never reduced against those of non-tidally perturbed galaxies. Star-forming regions in non-tidally perturbed galaxies are better candidates for SF suppression (quenching). The lowered SF with increasing stellar mass density in tidally perturbed galaxies may suggest a lower dependence of SF on stellar mass. Though the SFMS slopes, either flatter or steeper, are found independent of stellar mass density, the effect of global stellar mass cannot be ignored when distinguishing between galaxy types. Since a phenomenon or property other than local/global stellar mass may be taking part in the modulation of SF, the integrated SF properties are related to the tidal perturbation parameter. We find weak, but detectable, positive correlations for perturbed galaxies suggesting that tidal perturbations induced by close companions increase the gas accretion rates of these objects.
ABSTRACT In this second paper of the series, we present the two-dimensional (2D) emission line abundance analysis of NGC 628, the largest object within the PPAK Integral Field Spectroscopy (IFS) ...Nearby Galaxies Survey, PINGS. We introduce the methodology applied to the 2D IFS data in order to extract and deal with large spectral samples, from which a 2D abundance analysis can be later performed. We obtain the most complete and reliable abundance gradient of the galaxy up to date, by using the largest number of spectroscopic points sampled in the galaxy, and by comparing the statistical significance of different strong-line metallicity indicators. We find features not previously reported for this galaxy that imply a multimodality of the abundance gradient consistent with a nearly flat distribution in the innermost regions of the galaxy, a steep negative gradient along the disc and a shallow gradient or nearly constant metallicity beyond the optical edge of the galaxy. The N/O ratio seems to follow the same radial behaviour. We demonstrate that the observed dispersion in metallicity shows no systematic dependence with the spatial position, signal-to-noise ratio or ionization conditions, implying that the scatter in abundance for a given radius is reflecting a true spatial physical variation of the oxygen content. Furthermore, by exploiting the 2D IFS data, we were able to construct the 2D metallicity structure of the galaxy, detecting regions of metal enhancement and showing that they vary depending on the choice of the metallicity estimator. The analysis of axisymmetric variations in the disc of NGC 628 suggest that the physical conditions and the star formation history of different symmetric regions of the galaxy have evolved in a different manner. PUBLICATION ABSTRACT
ABSTRACT
The primordial helium abundance YP is calculated using sulphur as metallicity tracer in the classical methodology (with YP as an extrapolation of Y to zero metals). The calculated value, YP, ... S= 0.244 ± 0.006, is in good agreement with the estimate from the Planck experiment, as well as, determinations in the literature using oxygen as the metallicity tracer. The chemical analysis includes the substraction of the nebular continuum and of the stellar continuum computed from simple stellar population synthesis grids. The S+2 content is measured from the near-infrared $\left\mathrm{ S}\,\mathrm{ III}\right\lambda \lambda 9069,9532$ lines, while an ICF(S3 +) is proposed based on the Ar3 +/Ar2 + fraction. Finally, we apply a multivariable linear regression using simultaneously oxygen, nitrogen, and sulphur abundances for the same sample to determine the primordial helium abundance resulting in YP − O, N, S = 0.245 ± 0.007.
We use optical integral-field spectroscopic (IFS) data from 103 nearby galaxies at different stages of the merging event, from close pairs to merger remnants provided by the CALIFA survey, to study ...the impact of the interaction in the specific star formation and oxygen abundance on different galactic scales. To disentangle the effect of the interaction and merger from internal processes, we compared our results with a control sample of 80 non-interacting galaxies. We confirm the moderate enhancement (×2–3 times) of specific star formation for interacting galaxies in central regions as reported by previous studies; however, the specific star formation is comparable when observed in extended regions. We find that control and interacting star-forming galaxies have similar oxygen abundances in their central regions, when normalized to their stellar masses. Oxygen abundances of these interacting galaxies seem to decrease compared to the control objects at the large aperture sizes measured in effective radius. Although the enhancement in central star formation and lower metallicities for interacting galaxies have been attributed to tidally induced inflows, our results suggest that other processes such as stellar feedback can contribute to the metal enrichment in interacting galaxies.
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•Laminar numerical simulations have been conducted to understand the impinging process of a non-Newtonian fluid against a heated solid wall.•A power-law fluid has been used as working fluid.•Heat and ...momentum transfer have been characterized for different input parameters.•Both the mechanical and thermal results have been fitted to different mathematical correlations with reasonable accuracy.
In this paper we analyse the jet of non-Newtonian power law fluids emerging from a tube with a diameter D and impinging on a flat plate, which is receiving from the other side a constant heat flux. To that end, different numerical simulations have been carried out with the one dimensional fully developed axisymmetric velocity profile used as boundary condition to model the jet. The aim of the work is to quantify the heat (through the Nusselt number) and momentum (through the friction coefficient on the plate) transfer processes between the jet and the plate as a function of the Reynolds number (Re=50,100,200), the tube-to-plate distance (H/D=1,2,4) and the power law index (n=0.8,0.9,1.0,1.1,1.2). The values given to the power law index allowed to explore both the shear thickening and the shear thinning behaviours. Results showed that a larger tube-to-plate separation decreases both the transference of heat and momentum; additionally, increasing the Reynolds number improves the heat transfer in detriment of momentum transfer; and, similarly to this latter input parameter, lowering the power law index, increases the heat transfer and worsens the momentum transfer. These results are summarised in three mathematical correlations consisting of potential functions of the input parameters, i.e. Re,H/D and n. However, as it is usually done, the Prandtl number Pr will be used instead of n.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present the largest and most homogeneous catalog of H ii regions and associations compiled so far. The catalog comprises more than 7000 ionized regions, extracted from 306 galaxies observed by the ...CALIFA survey. We describe the procedures used to detect, select, and analyze the spectroscopic properties of these ionized regions. In the current study we focus on characterizing of the radial gradient of the oxygen abundance in the ionized gas, based on the study of the deprojecteddistribution of H ii regions. We found that all galaxies without clear evidence of an interaction present a common gradient in the oxygen abundance, with a characteristic slope of αO/H = −0.1 dex/re between 0.3 and 2 disk effective radii (re), and a scatter compatible with random fluctuations around this value, when the gradient is normalized to the disk effective radius. The slope is independent of morphology, the incidence of bars, absolute magnitude, or mass. Only those galaxies with evidence of interactions and/or clear merging systems present a significantly shallower gradient, consistent with previous results. The majority of the 94 galaxies with H ii regions detected beyond two disk effective radii present a flattening in the oxygen abundance. The flattening is statistically significant. We cannot provide a conclusive answer regarding the origin of this flattening. However, our results indicate that its origin is most probably related to the secular evolution of galaxies. Finally, we find a drop/truncation of the oxygen abundance in the inner regions for 26 of the galaxies. All of them are non-interacting, mostly unbarred Sb/Sbc galaxies. This feature is associated with a central star-forming ring, which suggests that both features are produced by radial gas flows induced by resonance processes. Our result suggests that galaxy disks grow inside-out, with metal enrichment driven by the local star formation history and with a small variation galaxy-by-galaxy. At a certain galactocentric distance, the oxygen abundance seems to be correlated well with the stellar mass density and total stellar mass of the galaxies, independently of other properties of the galaxies. Other processes, such as radial mixing and inflows/outflows seem to have a limited effect on shaping of the radial distribution of oxygen abundances, although they are not ruled out.
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We present a wide-field Integral Field Spectroscopy (IFS) survey on the nearby face-on Sbc galaxy NGC 628, comprising 11094 individual spectra, covering a nearly circular field-of-view of ∼6 arcmin ...in diameter, with a sampling of ∼2.7 arcsec per spectrum in the optical wavelength range (3700-7000 Å). This galaxy is part of the PPAK IFS Nearby Galaxies Survey (PINGS). To our knowledge, this is the widest spectroscopic survey ever made in a single nearby galaxy. A detailed flux calibration was applied, granting a spectrophotometric accuracy of ∼0.2 mag. The spectroscopic data were analysed both as a single integrated spectrum that characterizes the global properties of the galaxy and using each individual spectrum to determine the spatial variation of the stellar and ionized gas components. The spatial distribution of the luminosity-weighted ages and metallicities of the stellar populations was analysed. Using typical strong emission-line ratios we derived the integrated and 2D spatial distribution of the ionized gas, the dust content, star formation rate (SFR) and oxygen abundance.
The age of the stellar populations shows a negative gradient from the inner (older) to the outer (younger) regions. We found an inversion of this gradient in the central ∼1 kpc region, where a somewhat younger stellar population is present within a ring at this radius. This structure is associated with a circumnuclear star-forming region at ∼500 pc, also found in similar spiral galaxies. From the study of the integrated and spatially resolved ionized gas, we found a moderate SFR of ∼2.4 M⊙ yr−1. The oxygen abundance shows a clear gradient of higher metallicity values from the inner part to the outer part of the galaxy, with a mean value of 12 + log(O/H) ∼ 8.7. At some specific regions of the galaxy, the spatially resolved distribution of the physical properties shows some level of structure, suggesting real point-to-point variations within an individual H ii region. Our results are consistent with an inside-out growth scheme, with stronger star formation at the outer regions, and with evolved stellar populations in the inner ones.
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