The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on20...The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.展开更多
This work aims to analyze how hyperons affect neutrino radiation properties in nucleonic direct URCA processes,with the goal of providing useful references for identifying evidence of hyperons in astronomical observat...This work aims to analyze how hyperons affect neutrino radiation properties in nucleonic direct URCA processes,with the goal of providing useful references for identifying evidence of hyperons in astronomical observations.This analysis is conducted using the GM1 and NL3 parameter sets under the SU(6)and SU(3)flavor symmetries within the relativistic mean field theory framework.In conjunction with the inferred mass and radius values of PSRs J1231-1411,J0030+0451,and J0740+6620,our results indicate that nucleonic direct URCA processes are absent in PSR J1231-1411 due to momentum conservation violation.In the hyperon-containing PSR J0030+0451(NL3 parameter set),the nucleonic direct URCA processes involving e^(-)/μ^(-)would occur.A large inferred mass span induces hyperon fraction variations,which affect neutrino emissivity.If the inferred mass of PSR J0030+0451 exceeds approximately 1.8M_(⊙),the neutrino luminosity of the nucleonic direct URCA processes under the SU(3)flavor symmetry remains nearly the same as that in npeμmatter,independent of hyperons.However,it shows an obvious hyperon dependence under the SU(6)spin-flavor symmetry.For hyperon-containing J0740+6620,the nucleonic direct URCA processes under the SU(3)flavor symmetry in the GM1 parameter set predict a faster decline in neutrino luminosity with the hyperonic fraction than in npeμmatter,and under the SU(6)spin-flavor symmetry in the NL3 parameter set,it shows a monotonic decreasing trend.The research indicates that the hyperonic fraction significantly affects the neutrino radiation properties of nucleonic direct URCA processes in neutron stars.Different-mass pulsars(e.g.,PSRs J1231-1411,J0030+0451,J0740+6620)exhibit distinct behaviors of nucleonic direct URCA processes,depending on inferred masses/radii,parameter sets,and theoretical models.展开更多
基金supported by the Einstein Probe project,a mission in the Strategic Priority Program on Space Science of CAS(grant Nos.XDA15310000,XDA15052100)in part been supported by the European Union’s Horizon 2020 Program under the AHEAD2020 project(grant No.871158).
文摘The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field X-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July 27.In this paper,we introduce the design and on-ground test results of the LEIA instrument.Using stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the X-ray imager is realized.An optical assembly composed of 36 MPO chips is used to focus incident X-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane detectors.The instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of view.The detection passband is 0.5-4 keV in soft X-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s observation.The total weight of LEIA is 56 kg and the power is 85 W.The satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 minutes.LEIA is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for X-ray observation,and by optimizing the working setups of the instrumental parameters.In addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft X-ray band,albeit with limited useful observing time available.
基金Supported by the Development Project of Science and Technology of Jilin Province(20250102012JC)the Special Project for the Theoretical Basic Research of Changchun Satellite Observatory,National Astronomical Observatories,Chinese Academy of Sciences(Y990000205)。
文摘This work aims to analyze how hyperons affect neutrino radiation properties in nucleonic direct URCA processes,with the goal of providing useful references for identifying evidence of hyperons in astronomical observations.This analysis is conducted using the GM1 and NL3 parameter sets under the SU(6)and SU(3)flavor symmetries within the relativistic mean field theory framework.In conjunction with the inferred mass and radius values of PSRs J1231-1411,J0030+0451,and J0740+6620,our results indicate that nucleonic direct URCA processes are absent in PSR J1231-1411 due to momentum conservation violation.In the hyperon-containing PSR J0030+0451(NL3 parameter set),the nucleonic direct URCA processes involving e^(-)/μ^(-)would occur.A large inferred mass span induces hyperon fraction variations,which affect neutrino emissivity.If the inferred mass of PSR J0030+0451 exceeds approximately 1.8M_(⊙),the neutrino luminosity of the nucleonic direct URCA processes under the SU(3)flavor symmetry remains nearly the same as that in npeμmatter,independent of hyperons.However,it shows an obvious hyperon dependence under the SU(6)spin-flavor symmetry.For hyperon-containing J0740+6620,the nucleonic direct URCA processes under the SU(3)flavor symmetry in the GM1 parameter set predict a faster decline in neutrino luminosity with the hyperonic fraction than in npeμmatter,and under the SU(6)spin-flavor symmetry in the NL3 parameter set,it shows a monotonic decreasing trend.The research indicates that the hyperonic fraction significantly affects the neutrino radiation properties of nucleonic direct URCA processes in neutron stars.Different-mass pulsars(e.g.,PSRs J1231-1411,J0030+0451,J0740+6620)exhibit distinct behaviors of nucleonic direct URCA processes,depending on inferred masses/radii,parameter sets,and theoretical models.
