Abstract
We present a detailed prompt emission and early optical afterglow analysis of the two very-high-energy (VHE) detected bursts GRB 201015A and GRB 201216C, and their comparison with a subset ...of similar bursts. Time-resolved spectral analysis of multistructured GRB 201216C using the Bayesian binning algorithm revealed that during the entire duration of the burst, the low-energy spectral index (
α
pt
) remained below the limit of the synchrotron line of death. However, statistically some of the bins supported the additional thermal component. Additionally, the evolution of spectral parameters showed that both the peak energy (
E
p
) and
α
pt
tracked the flux. These results were further strengthened using the values of the physical parameters obtained by synchrotron modeling of the data. Our earliest optical observations of both bursts using the F/Photometric Robotic Atmospheric Monitor Observatorio del Roque de los Muchachos and Burst Observer and Optical Transient Exploring System robotic telescopes displayed a smooth bump in their early optical light curves, consistent with the onset of the afterglow due to synchrotron emission from an external forward shock. Using the observed optical peak, we constrained the initial bulk Lorentz factors of GRB 201015A and GRB 201216C to Γ
0
= 204 and Γ
0
= 310, respectively. The present early optical observations are the earliest known observations constraining outflow parameters and our analysis indicate that VHE detected bursts could have a diverse range of observed luminosity within the detectable redshift range of present VHE facilities.
Magnetars are strongly magnetized, isolated neutron stars
with magnetic fields up to around 10
gauss, luminosities of approximately 10
-10
ergs per second and rotation periods of about 0.3-12.0 s. ...Very energetic giant flares from galactic magnetars (peak luminosities of 10
-10
ergs per second, lasting approximately 0.1 s) have been detected in hard X-rays and soft γ-rays
, and only one has been detected from outside our galaxy
. During such giant flares, quasi-periodic oscillations (QPOs) with low (less than 150 hertz) and high (greater than 500 hertz) frequencies have been observed
, but their statistical significance has been questioned
. High-frequency QPOs have been seen only during the tail phase of the flare
. Here we report the observation of two broad QPOs at approximately 2,132 hertz and 4,250 hertz in the main peak of a giant γ-ray flare
in the direction of the NGC 253 galaxy
, disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere-Space Interactions Monitor instrument
aboard the International Space Station, which was the only instrument that recorded the main burst phase (0.8-3.2 milliseconds) in the full energy range (50 × 10
to 40 × 10
electronvolts) without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations, these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
The Burst Observer and Optical Transient Exploring System (BOOTES) was first designed as an asset of autonomous telescopes that started to be deployed in 1998, taking 24 years to be fully developed ...around the earth. Nowadays BOOTES has became a global network of robotic telescopes, being the first one present in all continents, as of 2022. Here we present the details of the network and review its achievements over the last 2 decades regarding follow-up observations of high-energy transient events. Moreover, considering the recent operations of neutrino and gravitational wave detectors, some hot-topic expectations related to robotic astronomy are discussed within the framework of multi-wavelength astrophysics.
Servicio de Hematologia Clinica, Institut Catala d'Oncologia-Hospital Universitari Germans Trias i Pujol, C/ Canyet S/N, 08916 Badalona, Spain. jmribera@ns.hugtip.scs.es
BACKGROUND AND OBJECTIVES: ...The optimal post-remission therapy for adults with high-risk acute lymphoblastic leukemia (ALL) is not well established. This multicenter randomized trial by the Spanish PETHEMA Group was addressed to compare three options of post-remission therapy in adults with high-risk ALL: chemotherapy, allogeneic stem cell transplantation (SCT) and autologous SCT. DESIGN AND METHODS: A total of 222 valid high-risk ALL patients entered the trial. All received a standard five-drug/five-week induction course. Patients in complete remission with an HLA-identical family donor were assigned to allogeneic SCT (n=84) and the remaining were randomized to autologous SCT (n=50) or to delayed intensification followed by maintenance chemotherapy up to 2 years in complete remission (n=48). RESULTS: Overall, 183 patients achieved complete remission (82%). With a median follow-up of 70 months, the median disease-free survival and overall survival were 17 and 23 months, respectively. The 5-year disease-free survival and overall survival were 35% (95% CI, 30%-41%) and 34% (95% CI, 28%-39%), respectively. Patients allocated to the chemotherapy, allogeneic and autologous SCT were comparable in the main pre-treatment ALL characteristics and the rate of response to therapy. Intention-to-treat analysis showed no differences between patients according to whether they had or did not have a donor in disease-free survival (39%, 95% CI 30-48% vs. 33%, 95% CI 23-41%) and overall survival (44%, 95% CI 35-52% vs. 35%, 95% CI 25-44%), as well as for autologous SCT vs. chemotherapy comparisons (disease-free survival: 40%, 95% CI 28-52% vs. 51%, 95% CI 37-67%; overall survival: 43%, 95% CI 29-58% vs. 52%, 95% CI 39-65%). No differences were observed when the analysis was made on the basis of the treatment actually performed. INTERPRETATION AND CONCLUSIONS: This study failed to prove that, when a family donor is available, allogeneic SCT produces a better outcome than autologous SCT or chemotherapy in adults with high-risk ALL.
The Burst Observer and Optical Transient Exploring System (BOOTES) was first designed as an asset of autonomous telescopes that started to be deployed in 1998, taking 24 years to be fully developed ...around the Earth. Nowadays BOOTES has became a global network of robotic telescopes, being the first one present in all continents, as of 2022. Here we present the details of the network and review its achievements over the last two decades regarding follow-up observations of high-energy transient events. Moreover, considering the recent operations of neutrino and gravitational wave detectors, some hot-topic expectations related to robotic astronomy are discussed within the framework of multi-wavelength astrophysics.
We present a detailed prompt emission and early optical afterglow analysis of the two very high energy (VHE) detected bursts GRB 201015A and GRB 201216C, and their comparison with a subset of similar ...bursts. Time-resolved spectral analysis of multi-structured GRB 201216C using the Bayesian binning algorithm revealed that during the entire duration of the burst, the low energy spectral index (\(\alpha_{\rm pt}\)) remained below the limit of the synchrotron line of death. However, statistically some of the bins supported the additional thermal component. Additionally, the evolution of spectral parameters showed that both peak energy (Ep) and \(\alpha_{\rm pt}\) tracked the flux. These results were further strengthened using the values of the physical parameters obtained by synchrotron modeling of the data. Our earliest optical observations of both bursts using FRAM-ORM and BOOTES robotic telescopes displayed a smooth bump in their early optical light curves, consistent with the onset of the afterglow due to synchrotron emission from an external forward shock. Using the observed optical peak, we constrained the initial bulk Lorentz factors of GRB 201015A and GRB 201216C to \(\Gamma_0\) = 204 and \(\Gamma_0\) = 310, respectively. The present early optical observations are the earliest known observations constraining outflow parameters and our analysis indicate that VHE-detected bursts could have a diverse range of observed luminosity within the detectable redshift range of present VHE facilities.
