12 research outputs found
Optical intra-day variability of the blazar S5 0716+714
We present an extensive recent multi-band optical photometric observations of
the blazar S5 0716+714 carried out over 53 nights with two telescopes in India,
two in Bulgaria, one in Serbia, and one in Egypt during 2019 November -- 2022
December. We collected 1401, 689, 14726, and 165 photometric image frames in B,
V, R, and I bands, respectively. We montiored the blazar quasi-simultaneously
during 3 nights in B, V, R, and I bands; 4 nights in B, V, and R; 2 nights in
V, R, and I; 5 nights in B and R; and 2 nights in V and R bands. We also took
37 nights of data only in R band. Single band data are used to study intraday
flux variability and two or more bands quasi-simultaneous observations allow us
to search for colour variation in the source. We employ the power-enhanced
F-test and the nested ANOVA test to search for genuine flux and color
variations in the light curves of the blazar on intraday timescales. Out of 12,
11, 53, and 5 nights observations, intraday variations with amplitudes between
~3% and ~20% are detected in 9, 8, 31 and 3 nights in B, V, R, and I bands,
respectively, corresponding to duty cycles of 75%, 73%, 58% and 60%. These duty
cycles are lower than those typically measured at earlier times. On these
timescales color variations with both bluer-when-brighter and
redder-when-brighter are seen, though nights with no measurable colour
variation are also present. We briefly discuss possible explanations for this
observed intraday variability.Comment: 19 pages, 5 figures, 4 tables, Accepted for Publication in MNRA
Multi-band analyses of the bright GRB~230812B and the associated SN2023pel
GRB~230812B is a bright and relatively nearby () long gamma-ray
burst that has generated significant interest in the community and therefore
has been subsequently observed over the entire electromagnetic spectrum. We
report over 80 observations in X-ray, ultraviolet, optical, infrared, and
sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for
Multi-messenger Addicts) network of observatories and from observational
partners. Adding complementary data from the literature, we then derive
essential physical parameters associated with the ejecta and external
properties (i.e. the geometry and environment) and compare with other analyses
of this event (e.g. Srinivasaragavan et al. 2023). We spectroscopically confirm
the presence of an associated supernova, SN2023pel, and we derive a
photospheric expansion velocity of v 17 km . We
analyze the photometric data first using empirical fits of the flux and then
with full Bayesian Inference. We again strongly establish the presence of a
supernova in the data, with an absolute peak r-band magnitude . We find a flux-stretching factor or relative brightness and a time-stretching factor ,
both compared to SN1998bw. Therefore, GRB 230812B appears to have a clear long
GRB-supernova association, as expected in the standard collapsar model.
However, as sometimes found in the afterglow modelling of such long GRBs, our
best fit model favours a very low density environment (). We also find small values for
the jet's core angle and
viewing angle. GRB 230812B/SN2023pel is one of the best characterized
afterglows with a distinctive supernova bump
Multiband analyses of the bright GRB 230812B and the associated SN2023pel
GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and submillimetre bands from the GRANDMA (Global Rapid Advanced Network for Multimessenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17 × 103 km s-1. We analyse the photometric data first using empirical fits of the flux and then with full Bayesian inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75 × 1042 erg s-1, at 15.76+-10.2181 d (in the observer frame) after the trigger, with a half-max time width of 22.0 d. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fitting model favours a very low density environment (log10(nISM/cm-3) = -2.38+-11.6045) and small values for the jet's core angle θcore = 1.54+-01.8102 deg and viewing angle θobs = 0.76+-01.7629 deg. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump
Ber-EP4, CK1, CK7 and CK14 are Useful Markers for Basaloid Squamous Carcinoma: A Study of 45 Cases
Diagnosis of basaloid squamous carcinoma (BSCC) currently relies mainly on histological criteria, with variable immunohistochemical results reported in small series. We explored the use of a battery of immunohistochemical stains to elucidate this diagnosis on 45 cases of BSCC. To further elucidate the immunohistochemical profile of BSCC, to explore potential genetic pathways of malignant transformation using proliferation markers, and to investigate a possible link with Human Papillomavirus (HPV). Forty-five cases of BSCC and 34 site-matched cases of squamous cell carcinoma (SCC) were obtained from the archives of the pathology department at our institution. Extensive literature review was undertaken utilizing Medline. Ber-EP4 is a useful diagnostic marker for BSCC, positive in 82% (37/45) of the cases and in 68% (23/34) of SCC. An alternative is the combination of cytokeratins CK14 and CK7, known to be negative, and CK1, known to be positive, which achieves an accuracy of 73% (33/45) in BSCC and 88% (30/34) in SCC. The two diagnostic approaches were in agreement in 66% of the cases; both methods were equally accurate in the divergent cases. Increased expression of the proliferation markers supports the concept that BSCC is a rapidly growing tumor. Results of p16 stains support an etiological link between BSCC and HPV; interestingly, HPV was present significantly more in BSCC (71% (32/45)), than in SCC (59% (20/34)) in this study (P = 0.02)
Multiband analyses of the bright GRB 230812B and the associated SN2023pel
GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and submillimetre bands from the GRANDMA (Global Rapid Advanced Network for Multimessenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17 × 103 km s-1. We analyse the photometric data first using empirical fits of the flux and then with full Bayesian inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75 × 1042 erg s-1, at 15.76+-10.2181 d (in the observer frame) after the trigger, with a half-max time width of 22.0 d. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fitting model favours a very low density environment (log10(nISM/cm-3) = -2.38+-11.6045) and small values for the jet's core angle θcore = 1.54+-01.8102 deg and viewing angle θobs = 0.76+-01.7629 deg. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump
Multi-band analyses of the bright GRB~230812B and the associated SN2023pel
International audienceGRB~230812B is a bright and relatively nearby () long gamma-ray burst that has generated significant interest in the community and therefore has been subsequently observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for Multi-messenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) and compare with other analyses of this event (e.g. Srinivasaragavan et al. 2023). We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v 17 km . We analyze the photometric data first using empirical fits of the flux and then with full Bayesian Inference. We again strongly establish the presence of a supernova in the data, with an absolute peak r-band magnitude . We find a flux-stretching factor or relative brightness and a time-stretching factor , both compared to SN1998bw. Therefore, GRB 230812B appears to have a clear long GRB-supernova association, as expected in the standard collapsar model. However, as sometimes found in the afterglow modelling of such long GRBs, our best fit model favours a very low density environment (). We also find small values for the jet's core angle and viewing angle. GRB 230812B/SN2023pel is one of the best characterized afterglows with a distinctive supernova bump
Multi-band analyses of the bright GRB~230812B and the associated SN2023pel
International audienceGRB~230812B is a bright and relatively nearby () long gamma-ray burst that has generated significant interest in the community and therefore has been subsequently observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for Multi-messenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) and compare with other analyses of this event (e.g. Srinivasaragavan et al. 2023). We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v 17 km . We analyze the photometric data first using empirical fits of the flux and then with full Bayesian Inference. We again strongly establish the presence of a supernova in the data, with an absolute peak r-band magnitude . We find a flux-stretching factor or relative brightness and a time-stretching factor , both compared to SN1998bw. Therefore, GRB 230812B appears to have a clear long GRB-supernova association, as expected in the standard collapsar model. However, as sometimes found in the afterglow modelling of such long GRBs, our best fit model favours a very low density environment (). We also find small values for the jet's core angle and viewing angle. GRB 230812B/SN2023pel is one of the best characterized afterglows with a distinctive supernova bump
Multi-band analyses of the bright GRB~230812B and the associated SN2023pel
International audienceGRB~230812B is a bright and relatively nearby () long gamma-ray burst that has generated significant interest in the community and therefore has been subsequently observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for Multi-messenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) and compare with other analyses of this event (e.g. Srinivasaragavan et al. 2023). We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v 17 km . We analyze the photometric data first using empirical fits of the flux and then with full Bayesian Inference. We again strongly establish the presence of a supernova in the data, with an absolute peak r-band magnitude . We find a flux-stretching factor or relative brightness and a time-stretching factor , both compared to SN1998bw. Therefore, GRB 230812B appears to have a clear long GRB-supernova association, as expected in the standard collapsar model. However, as sometimes found in the afterglow modelling of such long GRBs, our best fit model favours a very low density environment (). We also find small values for the jet's core angle and viewing angle. GRB 230812B/SN2023pel is one of the best characterized afterglows with a distinctive supernova bump
Multi-band analyses of the bright GRB~230812B and the associated SN2023pel
International audienceGRB~230812B is a bright and relatively nearby () long gamma-ray burst that has generated significant interest in the community and therefore has been subsequently observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for Multi-messenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) and compare with other analyses of this event (e.g. Srinivasaragavan et al. 2023). We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v 17 km . We analyze the photometric data first using empirical fits of the flux and then with full Bayesian Inference. We again strongly establish the presence of a supernova in the data, with an absolute peak r-band magnitude . We find a flux-stretching factor or relative brightness and a time-stretching factor , both compared to SN1998bw. Therefore, GRB 230812B appears to have a clear long GRB-supernova association, as expected in the standard collapsar model. However, as sometimes found in the afterglow modelling of such long GRBs, our best fit model favours a very low density environment (). We also find small values for the jet's core angle and viewing angle. GRB 230812B/SN2023pel is one of the best characterized afterglows with a distinctive supernova bump