Supernovae(SNe) are the most brilliant optical stellar-class explosions. Over the past two decades, several optical transient survey projects discovered more than-100 so-called superluminous supernovae(SLSNe) whose pe...Supernovae(SNe) are the most brilliant optical stellar-class explosions. Over the past two decades, several optical transient survey projects discovered more than-100 so-called superluminous supernovae(SLSNe) whose peak luminosities and radiated energy are ■ 7 × 10^(43) erg s^(-1) and > 10^(51) erg respectively, at least an order of magnitude larger than those of normal SNe. According to their optical spectra features, SLSNe have been split into two broad categories of type Ⅰ that are hydrogen-deficient and type Ⅱ that are hydrogen-rich. Investigating and determining the energy sources of SLSNe would be of outstanding importance for understanding their stellar evolution and explosion mechanisms. The energy sources of SLSNe can be determined by analyzing their light curves(LCs) and spectra. The most prevailing models accounting for the SLSN LCs are the ^(56)Ni cascade decay model, the magnetar spin-down model,the ejecta-circumstellar medium interaction model and the jet-ejecta interaction model. In this review, we present several energy-source models and their different combinations.展开更多
GRB 190530A was jointly observed by the High Energy X-ray Telescope of the Hard X-ray Modulation Telescope(Insight-HXMT/HE)and the Ground-Based Wide-Angle Camera network(GWAC-N)with the extremely large field of view.A...GRB 190530A was jointly observed by the High Energy X-ray Telescope of the Hard X-ray Modulation Telescope(Insight-HXMT/HE)and the Ground-Based Wide-Angle Camera network(GWAC-N)with the extremely large field of view.After triggered by Insight-HXMT/HE and Fermi/GBM,we observed the optical emission of GRB 190530A,using the 30 cm telescope of GWAC(GWAC-F30)to search and locate its position.Subsequent observation of the late afterglow of GRB 190530A was made with the 2.16 m telescope at Xinglong Observatory.In this paper,we make a detailed exploration of the origin of GRB 190530A.In the prompt emission,a“double-tracking”pattern is presented both for the low-energy spectral indexαand the peak energy Epin the Band function with Insight-HXMT/HE and Fermi/GBM data;the results of GRB 190530A are consistent with the Amati and Yonetoku correlations;the spectral lag(τ)versus energy(E)can be estimated withτ=-3.0±0.06+(0.17±0.03)logE.The synchrotron radiation can account for the origin of GRB190530A prompt emission behaviors.Theαand Epof the precursor are essentially the same as that of the main prompt emission,implying that they have the same origin.For the afterglow,it can be described with the external forward shock model in ISM circumburst medium.In summary,from precursor,prompt emission to afterglow of GRB 190530A all originated from synchrotron radiation.展开更多
We analyze the time and energy dependence of the Vela pulsar’s pulse profile using 13 yr observations from the Large Area Telescope on the Fermi Gamma-ray Space Telescope.It is found that the pulse profile of the Vel...We analyze the time and energy dependence of the Vela pulsar’s pulse profile using 13 yr observations from the Large Area Telescope on the Fermi Gamma-ray Space Telescope.It is found that the pulse profile of the Vela pulsar inγ-ray changes with time.We parameterize the pulse profile and find that different shape parameters show fiuctuations rather than gradual changes with time.However,these time variation trends are insignificant due to limited statistics.The pulse profile of the Vela pulsar displays clear energy dependence inγ-ray.Different shape parameters are accurately obtained or updated,especially the phase separations among different pulses.Their energy evolution trends are quantified for the first time,which will provide restrictions on currentγ-ray emission models.For the Vela pulsar,we also find a turning point at phase.Before and after this phase,the relative intensity of the pulse profile evolves with energy with the opposite trend.展开更多
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be class...We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.展开更多
基金supported by the National Key Research and Development Program of China (Grant No. 2017YFA0402600)the National Natural Science Foundation of China (Grant Nos. 11573014 and 11833003)
文摘Supernovae(SNe) are the most brilliant optical stellar-class explosions. Over the past two decades, several optical transient survey projects discovered more than-100 so-called superluminous supernovae(SLSNe) whose peak luminosities and radiated energy are ■ 7 × 10^(43) erg s^(-1) and > 10^(51) erg respectively, at least an order of magnitude larger than those of normal SNe. According to their optical spectra features, SLSNe have been split into two broad categories of type Ⅰ that are hydrogen-deficient and type Ⅱ that are hydrogen-rich. Investigating and determining the energy sources of SLSNe would be of outstanding importance for understanding their stellar evolution and explosion mechanisms. The energy sources of SLSNe can be determined by analyzing their light curves(LCs) and spectra. The most prevailing models accounting for the SLSN LCs are the ^(56)Ni cascade decay model, the magnetar spin-down model,the ejecta-circumstellar medium interaction model and the jet-ejecta interaction model. In this review, we present several energy-source models and their different combinations.
基金supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciencessupported by the National Key R&D Program of China(grant No.2021YFA0718500)+3 种基金the National Natural Science Foundation of China(grant Nos.U1938201,12103055,11863007 and 11973055)the Guangxi Science Foundation(grant No.2018GXNSFGA281007)the Innovation Project of Guangxi Graduate Education(grant No.YSCW2019050)the Teaching reform project of Guangxi Higher Education(grant No.2019JGZ102)。
文摘GRB 190530A was jointly observed by the High Energy X-ray Telescope of the Hard X-ray Modulation Telescope(Insight-HXMT/HE)and the Ground-Based Wide-Angle Camera network(GWAC-N)with the extremely large field of view.After triggered by Insight-HXMT/HE and Fermi/GBM,we observed the optical emission of GRB 190530A,using the 30 cm telescope of GWAC(GWAC-F30)to search and locate its position.Subsequent observation of the late afterglow of GRB 190530A was made with the 2.16 m telescope at Xinglong Observatory.In this paper,we make a detailed exploration of the origin of GRB 190530A.In the prompt emission,a“double-tracking”pattern is presented both for the low-energy spectral indexαand the peak energy Epin the Band function with Insight-HXMT/HE and Fermi/GBM data;the results of GRB 190530A are consistent with the Amati and Yonetoku correlations;the spectral lag(τ)versus energy(E)can be estimated withτ=-3.0±0.06+(0.17±0.03)logE.The synchrotron radiation can account for the origin of GRB190530A prompt emission behaviors.Theαand Epof the precursor are essentially the same as that of the main prompt emission,implying that they have the same origin.For the afterglow,it can be described with the external forward shock model in ISM circumburst medium.In summary,from precursor,prompt emission to afterglow of GRB 190530A all originated from synchrotron radiation.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11903001,U1938109,U1838201,U1838202 and 42004004)the Key Research Foundation of Education Ministry of Anhui Province(KJ2019A0787)the Doctor Foundation of Anhui Jianzhu University 2019(2019QDZ14)。
文摘We analyze the time and energy dependence of the Vela pulsar’s pulse profile using 13 yr observations from the Large Area Telescope on the Fermi Gamma-ray Space Telescope.It is found that the pulse profile of the Vela pulsar inγ-ray changes with time.We parameterize the pulse profile and find that different shape parameters show fiuctuations rather than gradual changes with time.However,these time variation trends are insignificant due to limited statistics.The pulse profile of the Vela pulsar displays clear energy dependence inγ-ray.Different shape parameters are accurately obtained or updated,especially the phase separations among different pulses.Their energy evolution trends are quantified for the first time,which will provide restrictions on currentγ-ray emission models.For the Vela pulsar,we also find a turning point at phase.Before and after this phase,the relative intensity of the pulse profile evolves with energy with the opposite trend.
基金the HXMT mission,a project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)supported by the National Key R&D Program of China(2016YFA0400800)the National Natural Science Foundation of China(Grant Nos.11673023,U1838201,U1838115,U1838111,U1838202,11733009 and U1838108)。
文摘We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.
