Core-collapse supernovae and host galaxy stellar populations
TL;DR: In this paper, the authors used images and spectra of the Sloan Digital Sky Survey (SDS) to examine the host galaxies of 519 nearby supernovae (SN) and found that the colors at the sites of the explosions, as well as chemical abundances, and specific star formation rates (SFRs) provided circumstantial evidence on the origin of each SN type.
Abstract: We have used images and spectra of the Sloan Digital Sky Survey to examine the host galaxies of 519 nearby supernovae (SN). The colors at the sites of the explosions, as well as chemical abundances, and specific star formation rates (SFRs) of the host galaxies provide circumstantial evidence on the origin of each SN type. We examine separately SN II, SN IIn, SN IIb, SN Ib, SN Ic, and SN Ic with broad lines (SN Ic-BL). For host galaxies that have multiple spectroscopic fibers, we select the fiber with host radial offset most similar to that of the SN. Type Ic SN explode at small host offsets, and their hosts have exceptionally strongly star-forming, metal-rich, and dusty stellar populations near their centers. The SN Ic-BL and SN IIb explode in exceptionally blue locations, and, in our sample, we find that the host spectra for SN Ic-BL show lower average oxygen abundances than those for SN Ic. SN IIb host fiber spectra are also more metal-poor than those for SN Ib, although a significant difference exists for only one of two strong-line diagnostics. SN Ic-BL host galaxy emission lines show strong central specific SFRs. In contrast, we find no strong evidence for different environments for SN IIn compared to the sites of SN II. Because our SN sample is constructed from a variety of sources, there is always a risk that sampling methods can produce misleading results. We have separated the SN discovered by targeted surveys from those discovered by galaxy-impartial searches to examine these questions and show that our results do not depend sensitively on the discovery technique.
Figures (18)
Table 4 Mean Redshifts for Each SN Type 
Table 3 SN Luminosity Functions 
Figure 2. Host galaxy u′ − z′ color vs. u′ surface brightness near SN location. The top panel plots the fraction of SN of each type with environments bluer than the horizontal axis coordinate, and the right panel plots the fraction of SN of each type whose environments have higher u′-band surface brightness than the vertical axis coordinate. SN IIb environments are bluer than SN Ib, SN Ic, and SN II environments (p = 0.03%, 0.2%, and 0.01%, respectively), and SN Ic-BL environments are bluer than those of SN Ib, SN Ic, and SN II (p = 0.04%, 0.09%, and 0.04%, respectively). SN Ib and SN Ic explode in regions with higher u′-band surface brightness than do SN II (p = 0.6% and 0.6%, respectively), and SN Ic sites have higher u′-band surface brightnesses than SN Ic-BL locations (3.8%). The aperture is the 20 host pixels with S/N > 1 in g′ band nearest the SN location. 
Table 5 K-S p-values for Combined Samples 
Figure 7. Ratio of stripped-envelope SN to SN II vs. oxygen abundance (T04 calibration). The comparatively high fraction of SN (Ib+Ib/c+Ic) to SN II at subsolar metallicity in the right lower panel favors contributions from a binary progenitor population or explosions even after collapse to a black hole. Color points correspond to spectroscopic metallicity measurements, and gray points correspond to metallicities estimated from stellar masses using the Tremonti et al. (2004) mass–metallicity relation. The comparatively high fraction of SN II host fiber spectra with contamination from AGN activity (present only in massive, metal-rich galaxies) excludes a considerable fraction of metal-rich SN II host galaxies, inflating the apparent fraction of stripped-envelope SN in metal-rich galaxies (color points). Indeed, the stripped-envelope fraction is smaller using metallicities estimated from host galaxy stellar masses (gray) which do not suffer from an AGN selection effect. Dashed line is Eldridge et al. (2008) prediction for binary progenitors; dotted line is Eldridge et al. (2008) prediction for non-rotating single progenitors; and solid and dash-dot lines are Georgy et al. (2009) predictions for single, rotating progenitors (where a minimum helium envelope of 0.6M separates SN Ib from SN Ic progenitors). Whether core collapse to a black hole can yield an SN explosion is not clear (e.g., Fryer et al. 1999), especially if high angular momentum does not support an accretion disk (Woosley et al. 1993). The Georgy et al. (2009) solid line prediction is where core collapse to a black hole produces SN while the dashed-line prediction is where core collapse to a black hole yields no SN. Vertical error bars reflect Poisson statistics while horizontal bars reflect the range of metallicities in each bin with the position of the vertical bar corresponding to the mean Z in the bin. Here, Z = 8.86 from Delahaye et al. (2010). 
Figure 1. Redshifts of SN discovered by galaxy-impartial surveys to z = 0.2 (left) and of SN discovered by targeted surveys in our sample (right). To increase the size of the sample, the left plot includes discoveries to z = 0.2, a higher upper limit than the z = 0.08 galaxy-impartial sample limit. Except for cosmic evolution, low-redshift galaxy-impartial surveys image the same galaxy populations at increasing redshift. This plot provides no suggestion that the detection efficiency functions, η(z, T ,mlim, C), for SN II, SN IIb, SN IIn, SN Ib, SN Ic, and SN Ic-BL vary differently with redshift, although the numbers of some species are small. The plot on the right shows the redshift distributions of the SN in our sample discovered by targeted surveys. Among the 15 possible two-sample comparisons, the most extreme difference is between the SN Ic and SN IIn distributions and has p = 1.1%. 
Table 7 Host Galaxy Measurements 
Table 8 Host Galaxy Measurements 
Figure 5. Host specific SFR estimated from SDSS 3′′ fiber spectrum with host radial offset most similar to that of SN explosion site. The sequence of the spectroscopic classes, arranged in order of the loss of the progenitor’s outer hydrogen and helium envelopes (i.e., SN II, SN IIb, SN Ib, SN Ic), exhibits increasing average host galaxy specific SFR (SFRM−1 yr−1), measured from SDSS fiber spectra. SN (Ib+Ic) hosts have greater specific SFR than SN II hosts (0.3%). SN Ic-BL hosts have greater specific SFR than SN II hosts (3.5%). SDSS fibers largely sample light within the host galaxy half-light radius and are often centered on the host galaxy nucleus. 
Figure 6. Host extinction estimated from 3′′ SDSS fiber spectrum with host radial offset most similar to that of SN explosion site. There is significant evidence that SN IIb and SN II hosts have less internal extinction than SN (Ib+Ic) host galaxies (p = 5.1% and 2.1%, respectively). The Drout et al. (2011) SN (Ib+Ic) AV extinction values estimated along the line of sight to the SN from light curve color and shape are consistent with the values we measure, although the spectroscopic fibers are largely not positioned at the SN site. 
Table 1 Galaxy-Impartial Sample Construction 
Figure 10. SDSS color composite images of six SN Ic-BL in our sample. SN Ic-BL in our sample occurred preferentially in lower-mass, low-metallicity host galaxies. Red cross hatches show SDSS fiber positions yielding oxygen abundance measurements. An additional red circle marks fibers whose host offsets are within 3 kpc of the SN offset. 
Figure 4. Host oxygen abundance measured from SDSS 3′′ fiber spectrum with host radial offset most similar to that of SN explosion site. While Tremonti et al. (2004) spectroscopic abundances are plotted, we also measure abundances using the Pettini & Pagel (2004) calibration. Even when we consider only SN discovered by galaxy-impartial surveys, we find a statistically significant difference between the SN Ic-BL and the SN Ic host abundance distributions (p = 2.1%/2.1%, respectively, for the T04/PP04 calibrations). When we consider only SN discovered by targeted surveys, we find a statistically significant difference between the SN IIb and the SN Ib host abundance distributions for one of two abundance diagnostics (p = 13%/1.8%, respectively, for the T04/PP04 calibrations). Evidence for a difference between the SN IIb and SN Ib host distributions strengthens when all SN discoveries are considered (8.5%/1.5%). 
Table 2 Targeted Sample Construction 
Figure 9. SDSS color composite images of six SN IIb in our sample. Their local environments are substantially bluer than those of SN Ib, SN Ic, and SN II. Red cross hatches show SDSS fiber positions yielding oxygen abundance measurements. An additional red circle marks fibers whose host offsets are within 3 kpc of the SN offset. 
Figure 3. Stellar masses of host galaxies vs. SN host offset, deprojected and normalized by host g′-band half-light radius. The top panel plots the fraction of each SN type with hosts less massive than the horizontal axis coordinate, and the right panel plots the fraction of SN of each type whose host offsets are greater than the vertical axis coordinate. SN Ic-BL are found in significantly less massive galaxies than are the SN Ib, SN Ic, or SN II (p = 0.2%, 0.4%, and 0.4%, respectively). Host galaxy stellar masses are estimated from PEGASE2 fits to u′g′r ′i′z′ host magnitudes. A two-sample K-S test finds evidence (p = 8.3%) that SN IIb explode at larger host offsets than SN Ib, among the SN discovered in galaxies with log M > 9.5. SN Ic explode closer to their host centers than SN II (p = 0.6%). 
Table 6 K-S p-values for Different Samples 
Figure 8. SDSS color composite images of six SN Ib, SN Ic, and SN II host galaxies in our sample. These include: SN 1990B (Ic), SN 2004cc (Ic), SN 2000de (Ib), SN 2001dc (IIP), SN 2004bs (Ib), SN 2004ec (IIn), and SN 2008ew (Ic). Red cross hatches show SDSS fiber positions yielding oxygen abundance measurements. An additional red circle marks fibers whose host offsets are within 3 kpc of the SN offset.
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TL;DR: A review of nearly a decade of short gamma-ray bursts and their afterglow and host-galaxy observations is presented in this article, where the authors use this information to shed light on the nature and properties of their progenitors, the energy scale and collimation of the relativistic outflow, and the properties of the circumburst environments.
Abstract: Gamma-ray bursts (GRBs) display a bimodal duration distribution with a separation between the short- and long-duration bursts at about 2 s. The progenitors of long GRBs have been identified as massive stars based on their association with Type Ic core-collapse supernovae (SNe), their exclusive location in star-forming galaxies, and their strong correlation with bright UV regions within their host galaxies. Short GRBs have long been suspected on theoretical grounds to arise from compact object binary mergers (neutron star–neutron star or neutron star–black hole). The discovery of short GRB afterglows in 2005 provided the first insight into their energy scale and environments, as well as established a cosmological origin, a mix of host-galaxy types, and an absence of associated SNe. In this review, I summarize nearly a decade of short GRB afterglow and host-galaxy observations and use this information to shed light on the nature and properties of their progenitors, the energy scale and collimation of the relativistic outflow, and the properties of the circumburst environments. The preponderance of the evidence points to compact object binary progenitors, although some open questions remain. On the basis of this association, observations of short GRBs and their afterglows can shed light on the on- and off-axis electromagnetic counterparts of gravitational wave sources from the Advanced LIGO/Virgo experiments.
1,061 citations
Cites background from "Core-collapse supernovae and host g..."
...…that track star formation activity with a short delay (i.e., massive stars) we expect direct spatial correlation with the underlying rest-frame UV light (as found for long GRBs and core-collapse SNe;Fruchter et al. 2006; Kelly, Kirshner & Pahre 2008; Svensson et al. 2010; Kelly & Kirshner 2012)....
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01 Aug 2006
TL;DR: In this article, distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS) were presented.
Abstract: We present distance measurements to 71 high redshift type Ia supernovae discovered during the first year of the 5-year Supernova Legacy Survey (SNLS). These events were detected and their multi-color light-curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshift. With this data set, we have built a Hubble diagram extending to z = 1, with all distance measurements involving at least two bands. Systematic uncertainties are evaluated making use of the multiband photometry obtained at CFHT. Cosmological fits to this first year SNLS Hubble diagram give the following results: {Omega}{sub M} = 0.263 {+-} 0.042 (stat) {+-} 0.032 (sys) for a flat {Lambda}CDM model; and w = -1.023 {+-} 0.090 (stat) {+-} 0.054 (sys) for a flat cosmology with constant equation of state w when combined with the constraint from the recent Sloan Digital Sky Survey measurement of baryon acoustic oscillations.
840 citations
TL;DR: The Zwicky Transient Facility (ZTF) as discussed by the authors is a new time domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg$^2$ field of view and 8 second readout time.
Abstract: The Zwicky Transient Facility (ZTF), a public-private enterprise, is a new time domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg$^2$ field of view and 8 second readout time. It is well positioned in the development of time domain astronomy, offering operations at 10% of the scale and style of the Large Synoptic Survey Telescope (LSST) with a single 1-m class survey telescope. The public surveys will cover the observable northern sky every three nights in g and r filters and the visible Galactic plane every night in g and r. Alerts generated by these surveys are sent in real time to brokers. A consortium of universities which provided funding ("partnership") are undertaking several boutique surveys. The combination of these surveys producing one million alerts per night allows for exploration of transient and variable astrophysical phenomena brighter than r $\sim$ 20.5 on timescales of minutes to years. We describe the primary science objectives driving ZTF including the physics of supernovae and relativistic explosions, multi-messenger astrophysics, supernova cosmology, active galactic nuclei and tidal disruption events, stellar variability, and Solar System objects.
501 citations
TL;DR: In this article, the bolometric light curve of 38 stripped-envelope core-collapse supernovae (SE SNe) is recovered and template light curves provided.
Abstract: Literature data are collated for 38 stripped-envelope core-collapse supernovae (SE SNe; i.e. SNe IIb, Ib, Ic and Ic-BL) that have good light curve coverage in more than one optical band. Using bolometric corrections derived in previous work, the bolometric light curve of each SN is recovered and template bolometric light curves provided. Peak light distributions and decay rates are investigated; SNe subtypes are not cleanly distinguished in this parameter space, although some grouping of types does occur and there is a suggestion of a Phillips-like relation for most SNe Ic-BL. The bolometric light curves are modelled with a simple analytical prescription and compared to results from more detailed modelling. Distributions of the explosion parameters shows the extreme nature of SNe Ic-BL in terms of their 56Ni mass and the kinetic energy, however ejected masses are similar to other subtypes. SNe Ib and Ic have very similar distributions of explosion parameters, indicating a similarity in progenitors. SNe~IIb are the most homogeneous subtype and have the lowest average values for 56Ni mass, ejected mass, and kinetic energy. Ejecta masses for each subtype and SE SNe as a whole are inconsistent with those expected from very massive stars. The majority of the ejecta mass distribution is well described by more moderately massive progenitors in binaries, indicating these are the dominant progenitor channel for SE SNe.
312 citations
Cites background from "Core-collapse supernovae and host g..."
...…hosts (e.g. Anderson & James 2008; Boissier & Prantzos 2009; Anderson et al. 2010; Leloudas et al. 2011; Modjaz et al. 2011; Anderson et al. 2012; Kelly & Kirshner 2012; Crowther 2013), the stellar populations surrounding SNe (e.g. Kuncarayakti et al. 2013; Williams et al. 2014), and SN rates…...
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Harvard University1, Yale University2, Space Telescope Science Institute3, University of Illinois at Urbana–Champaign4, University of Maryland, College Park5, University of Hawaii at Manoa6, University of Turku7, University of California, Santa Cruz8, University of Texas at Austin9, Johns Hopkins University10, Queen's University Belfast11, Max Planck Society12, Durham University13, Princeton University14
TL;DR: The results from a search within the Pan-STARRS1 Medium Deep Survey (PS1-MDS) for rapidly evolving and luminous transients are presented in this article.
Abstract: In the past decade, several rapidly evolving transients have been discovered whose timescales and luminosities are not easily explained by traditional supernovae (SNe) models The sample size of these objects has remained small due, at least in part, to the challenges of detecting short timescale transients with traditional survey cadences Here we present the results from a search within the Pan-STARRS1 Medium Deep Survey (PS1-MDS) for rapidly evolving and luminous transients We identify 10 new transients with a time above half-maximum (t 1/2) of less than 12 days and –165 > M > –20 mag This increases the number of known events in this region of SN phase space by roughly a factor of three The median redshift of the PS1-MDS sample is z = 0275 and they all exploded in star-forming galaxies In general, the transients possess faster rise than decline timescale and blue colors at maximum light (g P1 – r P1 lsim –02) Best-fit blackbodies reveal photospheric temperatures/radii that expand/cool with time and explosion spectra taken near maximum light are dominated by a blue continuum, consistent with a hot, optically thick, ejecta We find it difficult to reconcile the short timescale, high peak luminosity (L > 1043 erg s–1), and lack of UV line blanketing observed in many of these transients with an explosion powered mainly by the radioactive decay of 56Ni Rather, we find that many are consistent with either (1) cooling envelope emission from the explosion of a star with a low-mass extended envelope that ejected very little (<003 M ☉) radioactive material, or (2) a shock breakout within a dense, optically thick, wind surrounding the progenitor star After calculating the detection efficiency for objects with rapid timescales in the PS1-MDS we find a volumetric rate of 4800-8000 events yr–1 Gpc–3 (4%-7% of the core-collapse SN rate at z = 02)
309 citations
Cites background or methods from "Core-collapse supernovae and host g..."
...The entire corecollapse SN sample from Kelly & Kirshner (2012) (solid green line) is shifted to even higher metallicities than our sample, although we caution a fraction of these events were discovered by targeted surveys (which bias towards higher metallicities)....
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...Also shown are type Ia SN (Galbany et al. 2012, blue), type Ibc and type II SN (Kelly & Kirshner 2012, green and cyan, respectively) and the same LGRB and SGRB samples as described above....
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References
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University of California, Berkeley1, Lawrence Berkeley National Laboratory2, Instituto Superior Técnico3, Pierre-and-Marie-Curie University4, Stockholm University5, European Southern Observatory6, Collège de France7, University of Cambridge8, University of Barcelona9, Yale University10, Space Telescope Science Institute11, European Space Agency12, University of New South Wales13
TL;DR: In this paper, the mass density, Omega_M, and cosmological-constant energy density of the universe were measured using the analysis of 42 Type Ia supernovae discovered by the Supernova Cosmology project.
Abstract: We report measurements of the mass density, Omega_M, and
cosmological-constant energy density, Omega_Lambda, of the universe based on
the analysis of 42 Type Ia supernovae discovered by the Supernova Cosmology
Project. The magnitude-redshift data for these SNe, at redshifts between 0.18
and 0.83, are fit jointly with a set of SNe from the Calan/Tololo Supernova
Survey, at redshifts below 0.1, to yield values for the cosmological
parameters. All SN peak magnitudes are standardized using a SN Ia lightcurve
width-luminosity relation. The measurement yields a joint probability
distribution of the cosmological parameters that is approximated by the
relation 0.8 Omega_M - 0.6 Omega_Lambda ~= -0.2 +/- 0.1 in the region of
interest (Omega_M <~ 1.5). For a flat (Omega_M + Omega_Lambda = 1) cosmology we
find Omega_M = 0.28{+0.09,-0.08} (1 sigma statistical) {+0.05,-0.04}
(identified systematics). The data are strongly inconsistent with a Lambda = 0
flat cosmology, the simplest inflationary universe model. An open, Lambda = 0
cosmology also does not fit the data well: the data indicate that the
cosmological constant is non-zero and positive, with a confidence of P(Lambda >
0) = 99%, including the identified systematic uncertainties. The best-fit age
of the universe relative to the Hubble time is t_0 = 14.9{+1.4,-1.1} (0.63/h)
Gyr for a flat cosmology. The size of our sample allows us to perform a variety
of statistical tests to check for possible systematic errors and biases. We
find no significant differences in either the host reddening distribution or
Malmquist bias between the low-redshift Calan/Tololo sample and our
high-redshift sample. The conclusions are robust whether or not a
width-luminosity relation is used to standardize the SN peak magnitudes.
16,838 citations
TL;DR: In this article, the authors used spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 " z " 0.62.
Abstract: We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 " z " 0.62. The luminosity distances of these objects are determined by methods that employ relations between SN Ia luminosity and light curve shape. Combined with previous data from our High-z Supernova Search Team and recent results by Riess et al., this expanded set of 16 high-redshift supernovae and a set of 34 nearby supernovae are used to place constraints on the following cosmo- logical parameters: the Hubble constant the mass density the cosmological constant (i.e., the (H 0 ), () M ), vacuum energy density, the deceleration parameter and the dynamical age of the universe ) " ), (q 0 ), ) M \ 1) methods. We estimate the dynamical age of the universe to be 14.2 ^ 1.7 Gyr including systematic uncer- tainties in the current Cepheid distance scale. We estimate the likely e†ect of several sources of system- atic error, including progenitor and metallicity evolution, extinction, sample selection bias, local perturbations in the expansion rate, gravitational lensing, and sample contamination. Presently, none of these e†ects appear to reconcile the data with and ) " \ 0 q 0 " 0.
16,674 citations
TL;DR: In this article, a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed, is presented.
Abstract: We present a full-sky 100 μm map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100 and 240 μm data, we have constructed a map of the dust temperature so that the 100 μm map may be converted to a map proportional to dust column density. The dust temperature varies from 17 to 21 K, which is modest but does modify the estimate of the dust column by a factor of 5. The result of these manipulations is a map with DIRBE quality calibration and IRAS resolution. A wealth of filamentary detail is apparent on many different scales at all Galactic latitudes. In high-latitude regions, the dust map correlates well with maps of H I emission, but deviations are coherent in the sky and are especially conspicuous in regions of saturation of H I emission toward denser clouds and of formation of H2 in molecular clouds. In contrast, high-velocity H I clouds are deficient in dust emission, as expected. To generate the full-sky dust maps, we must first remove zodiacal light contamination, as well as a possible cosmic infrared background (CIB). This is done via a regression analysis of the 100 μm DIRBE map against the Leiden-Dwingeloo map of H I emission, with corrections for the zodiacal light via a suitable expansion of the DIRBE 25 μm flux. This procedure removes virtually all traces of the zodiacal foreground. For the 100 μm map no significant CIB is detected. At longer wavelengths, where the zodiacal contamination is weaker, we detect the CIB at surprisingly high flux levels of 32 ± 13 nW m-2 sr-1 at 140 μm and of 17 ± 4 nW m-2 sr-1 at 240 μm (95% confidence). This integrated flux ~2 times that extrapolated from optical galaxies in the Hubble Deep Field. The primary use of these maps is likely to be as a new estimator of Galactic extinction. To calibrate our maps, we assume a standard reddening law and use the colors of elliptical galaxies to measure the reddening per unit flux density of 100 μm emission. We find consistent calibration using the B-R color distribution of a sample of the 106 brightest cluster ellipticals, as well as a sample of 384 ellipticals with B-V and Mg line strength measurements. For the latter sample, we use the correlation of intrinsic B-V versus Mg2 index to tighten the power of the test greatly. We demonstrate that the new maps are twice as accurate as the older Burstein-Heiles reddening estimates in regions of low and moderate reddening. The maps are expected to be significantly more accurate in regions of high reddening. These dust maps will also be useful for estimating millimeter emission that contaminates cosmic microwave background radiation experiments and for estimating soft X-ray absorption. We describe how to access our maps readily for general use.
15,988 citations
"Core-collapse supernovae and host g..." refers methods in this paper
...We correct for Galactic reddening using the Schlegel et al. (1998) dust maps....
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TL;DR: In this paper, the authors presented a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed.
Abstract: We present a full sky 100 micron map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100 micron and 240 micron data, we have constructed a map of the dust temperature, so that the 100 micron map can be converted to a map proportional to dust column density. The result of these manipulations is a map with DIRBE-quality calibration and IRAS resolution.
To generate the full sky dust maps, we must first remove zodiacal light contamination as well as a possible cosmic infrared background (CIB). This is done via a regression analysis of the 100 micron DIRBE map against the Leiden- Dwingeloo map of H_I emission, with corrections for the zodiacal light via a suitable expansion of the DIRBE 25 micron flux. For the 100 micron map, no significant CIB is detected. In the 140 micron and 240 micron maps, where the zodiacal contamination is weaker, we detect the CIB at surprisingly high flux levels of 32 \pm 13 nW/m^2/sr at 140 micron, and 17 \pm 4 nW/m^2/sr at 240 micron (95% confidence). This integrated flux is ~2 times that extrapolated from optical galaxies in the Hubble Deep Field.
The primary use of these maps is likely to be as a new estimator of Galactic extinction. We demonstrate that the new maps are twice as accurate as the older Burstein-Heiles estimates in regions of low and moderate reddening. These dust maps will also be useful for estimating millimeter emission that contaminates CMBR experiments and for estimating soft X-ray absorption.
14,295 citations
TL;DR: In this paper, the authors present observations of 10 type Ia supernovae (SNe Ia) between 0.16 0 and 4.0 sigma confidence levels, for two fitting methods respectively.
Abstract: We present observations of 10 type Ia supernovae (SNe Ia) between 0.16 0) and a current acceleration of the expansion (i.e., q_0 0, the spectroscopically confirmed SNe Ia are consistent with q_0 0 at the 3.0 sigma and 4.0 sigma confidence levels, for two fitting methods respectively. Fixing a ``minimal'' mass density, Omega_M=0.2, results in the weakest detection, Omega_Lambda>0 at the 3.0 sigma confidence level. For a flat-Universe prior (Omega_M+Omega_Lambda=1), the spectroscopically confirmed SNe Ia require Omega_Lambda >0 at 7 sigma and 9 sigma level for the two fitting methods. A Universe closed by ordinary matter (i.e., Omega_M=1) is ruled out at the 7 sigma to 8 sigma level. We estimate the size of systematic errors, including evolution, extinction, sample selection bias, local flows, gravitational lensing, and sample contamination. Presently, none of these effects reconciles the data with Omega_Lambda=0 and q_0 > 0.
14,295 citations
"Core-collapse supernovae and host g..." refers background in this paper
...Surveys that we considered galaxy-impartial are as follows: Catalina Real-Time Sky Survey and Siding Spring Survey (Djorgovski et al. 2011), La Sagra Sky Survey, PAN-STARRS (Kaiser et al. 2010), Palomar Transient Factory (Law et al. 2009), ROTSE (Yost et al. 2006), ESSENCE (Miknaitis et al. 2007), PalomarQuest (Djorgovski et al. 2008), SDSS-II (Sako et al. 2005), Supernova Legacy Survey (Astier et al. 2006), Supernova Cosmology Project (Perlmutter et al. 1999), Near Earth Asteroid Tracking Program (Pravdo et al. 1999), High-z Supernova Search (Riess et al. 1998), Experience de Recherche dObjets Sombres (EROS) 7 http://www.cfa.harvard.edu/iau/lists/Supernovae.html (Hardin et al. 2000), Great Observatories Origins Deep Survey (GOODS) (Dickinson et al. 2003), Deep Lens Survey (Wittman et al. 2002), and, except for discoveries in targets IC342, M33, M74, M81, NGC 6984, and NGC 7331, the Texas Supernova Search (Quimby et al. 2005b)....
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...…al. 2006), Supernova Cosmology Project (Perlmutter et al. 1999), Near Earth Asteroid Tracking Program (Pravdo et al. 1999), High-z Supernova Search (Riess et al. 1998), Experience de Recherche dObjets Sombres (EROS) 7 http://www.cfa.harvard.edu/iau/lists/Supernovae.html (Hardin et al. 2000), Great…...
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