Gamma-ray burst (GRB) afterglows are powerful probes for studying the different properties of their host galaxies (e.g., the interstellar dust) at all redshifts. By fitting their spectral energy ...distribution (SED) over a large range of wavelengths, we can gain direct insights into the properties of the interstellar dust by studying the extinction curves. Unlike the dust extinction templates, such as those of the average Milky Way (MW) or the Small and Large Magellanic Cloud (SMC and LMC), the extinction curves of galaxies outside the Local Group exhibit deviation from these laws. Altogether, X-ray and gamma-ray satellites as well as ground-based telescopes, such as Neil Gehrels Swift Observatory ( Swift and Gamma-Ray Optical and Near-Infrared Detector (GROND), provide measurements of the afterglows from the X-ray to the NIR, which can be used to extract information on dust extinction curves along their lines of sight (LoS). The study presented in this paper undertakes such a photometric study, comprising a preparatory work for the SVOM mission and its ground-based follow-up telescope COLIBRI. We propose a simple approach to parameterize the dust extinction curve of GRB host galaxies. The model used in this analysis is based on a power law form with the addition of a Loretzian-like Drude profile with two parameters: the extinction slope, gamma , and the 2175 AA bump amplitude, $E_ b Using the g'r'i'z'JHK$ _s GROND filter bands, we tested our dust extinction model and explored the parameter space in extinction and redshift by fitting SEDs of simplified simulations of GRB afterglow spectra based on different extinction curve templates. From a final sample of 10 real Swift /GROND extinguished GRBs, we determined the quantities of the dust extinction in their host and measured their extinction curves. We find that our derived extinction curves are in agreement with the spectroscopic measurements reported for four GRBs in the literature. We compared four other GRBs to the results of photometric studies where fixed laws were used to fit their data. We additionally derived two new GRB extinction curves. The measured average extinction curve is given by a slope of gamma = 1.051pm 0.129 and $E_ b $ = 0.070pm 0.036, which is equivalent to a quasi-featureless in-between SMC-LMC template. This is consistent with previous studies aimed at deriving the dust host galaxy extinction where we expect that small dust grains dominate in GRB environment, yielding a steeper curve than the mean MW extinction curve.
The Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS) has created a large homogeneous database of intermediate redshift (0.2 < z < 1.0) type Ia supernovae (SNe Ia). The SNLS team has ...shown that correlations exist between SN Ia rates, properties, and host galaxy star formation rates. The SNLS SN Ia database has now been combined with a photometric redshift galaxy catalog and an optical galaxy cluster catalog to investigate the possible influence of galaxy clustering on the SN Ia rate, over and above the expected effect due to the dependence of SFR on clustering through the morphology-density relation. We identify three cluster SNe Ia, plus three additional possible cluster SNe Ia, and find the SN Ia rate per unit mass in clusters at intermediate redshifts is consistent with the rate per unit mass in field early-type galaxies and the SN Ia cluster rate from low redshift cluster targeted surveys. We also find the number of SNe Ia in cluster environments to be within a factor of two of expectations from the two component SNIa rate model.
This study determined the student profile and enrolment of the three Universities in the University Belt. It also found out the respondents' level of consideration concerning the institutional image ...indicators that served as basis for attracting prospective entrants. Descriptive statistics revealed the following: most of the respondents belonged to families with five members and lived in family-owned houses in the cities of Manila and Quezon; most of the respondents were taking up Medicine-related courses; most of FEU and UE respondents belonged to less- than-Php 30,000-monthly family income bracket, while UST respondents belonged to greater-than-Php 100,000-monthly family income; and UST had the most number of respondents with family members studying in the same school. A Geographical Information System-generated map also showed that there were more respondents from Marikina than from the nearby municipality of San Juan. For non-Metro Manila settlers, most of the respondents were from the provinces of CALABARZON (Region 4-A) or Central Luzon (Region 3). The three sets of respondents considered five indicators but had different levels of considerations in six indicators. Analysis of variance (ANOVA) showed that five out of six indicators were found to have a significant difference in the level of consideration. Further comparison was utilised through the use of Tukey-HSD. Thus, the hypothesis stating that there is no significant difference in the level of consideration of the respondents from the three Universities regarding institutional-image indicators is partially upheld. Author abstract, ed
We combine high-redshift Type Ia supernovae from the first three years of the Supernova Legacy Survey (SNLS) with other supernova (SN) samples, primarily at lower redshifts, to form a high-quality ...joint sample of 472 SNe (123 low-z, 93 SDSS, 242 SNLS, and 14 Hubble Space Telescope). SN data alone require cosmic acceleration at >99.999% confidence, including systematic effects. For the dark energy equation of state parameter (assumed constant out to at least z = 1.4) in a flat universe, we find w = --0.91+0.16 --0.20(stat)+0.07 --0.14(sys) from SNe only, consistent with a cosmological constant. Our fits include a correction for the recently discovered relationship between host-galaxy mass and SN absolute brightness. We pay particular attention to systematic uncertainties, characterizing them using a systematic covariance matrix that incorporates the redshift dependence of these effects, as well as the shape-luminosity and color-luminosity relationships. Unlike previous work, we include the effects of systematic terms on the empirical light-curve models. The total systematic uncertainty is dominated by calibration terms. We describe how the systematic uncertainties can be reduced with soon to be available improved nearby and intermediate-redshift samples, particularly those calibrated onto USNO/SDSS-like systems.
Cervicofacial actinomycosis is a chronic suppurative and granulomatous infection that may reside for years and recur with sudden onset. It is the second most common type of actinomycosis and could be ...caused by trauma or infection. We report a draining actinomycotic sinus tract with extraordinary thickness that occurred owing to a long-standing chronic periapical infection of an extracted upper left second premolar 3 years before.
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