The mass and distance functions of free-floating planets(FFPs) would give major insights into the formation and evolution of planetary systems, including any systematic differences between those in the disk and bulge....The mass and distance functions of free-floating planets(FFPs) would give major insights into the formation and evolution of planetary systems, including any systematic differences between those in the disk and bulge. We show that the only way to measure the mass and distance of individual FFPs over a broad range of distances is to observe them simultaneously from two observatories separated by D ~ O(0.01 au)(to measure their microlens parallax πE) and to focus on the finite-source point-lens(FSPL) events(which yield the Einstein radius θE). By combining the existing KMTNet 3-telescope observatory with a 0.3 m 4 deg2 telescope at L2, of order 130 such measurements could be made over four years, down to about M ~ 6 M⊕for bulge FFPs and M ~ 0.7 M⊕for disk FFPs. The same experiment would return masses and distances for many bound planetary systems. A more ambitious experiment, with two 0.5 m satellites(one at L2 and the other nearer Earth) and similar camera layout but in the infrared, could measure masses and distances of sub-Moon mass objects, and thereby probe(and distinguish between) genuine sub-Moon FFPs and sub-Moon "dwarf planets" in exo-Kuiper Belts and exo-Oort Clouds.展开更多
Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, ...Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00076.展开更多
基金support by the National Science Foundation of China (Grant Nos. 11821303 and 11761131004)supported by National Key R&D Program of China No.2019YFA0405100。
文摘The mass and distance functions of free-floating planets(FFPs) would give major insights into the formation and evolution of planetary systems, including any systematic differences between those in the disk and bulge. We show that the only way to measure the mass and distance of individual FFPs over a broad range of distances is to observe them simultaneously from two observatories separated by D ~ O(0.01 au)(to measure their microlens parallax πE) and to focus on the finite-source point-lens(FSPL) events(which yield the Einstein radius θE). By combining the existing KMTNet 3-telescope observatory with a 0.3 m 4 deg2 telescope at L2, of order 130 such measurements could be made over four years, down to about M ~ 6 M⊕for bulge FFPs and M ~ 0.7 M⊕for disk FFPs. The same experiment would return masses and distances for many bound planetary systems. A more ambitious experiment, with two 0.5 m satellites(one at L2 and the other nearer Earth) and similar camera layout but in the infrared, could measure masses and distances of sub-Moon mass objects, and thereby probe(and distinguish between) genuine sub-Moon FFPs and sub-Moon "dwarf planets" in exo-Kuiper Belts and exo-Oort Clouds.
基金supported by the National SKA Program of China (Grant Nos. 2020SKA0120100 and 2020SKA0120200)the National Natural Science Foundation of China (Grant Nos. 12041304, 11873067, 11988101, 12041303, 11725313, 11725314, 11833003, 12003028, 12041306, 12103089, U2031209, U2038105, and U1831207)+8 种基金the National Key Research and Development Program of China (Grant Nos. 2019YFA0405100, 2017YFA0402602, 2018YFA0404204, and 2016YFA0400801)Key Research Program of the Chinese Academy of Sciences (Grant No. QYZDJ-SSW-SLH021)Natural Science Foundation of Jiangsu Province (Grant No. BK20211000)Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS, the Strategic Priority Research Program on Space Science, the Western Light Youth Project of Chinese Academy of Sciences (Grant Nos. XDA15360000, XDA15052700, and XDB23040400)funding from the MaxPlanck Partner Group, the science research grants from the China Manned Space Project (Grant Nos. CMS-CSST2021-B11 and CMS-CSST-2021-A11)PKU development (Grant No. 7101502590)support from the XPLORER PRIZEsupported by Fundamental Research Funds for the Central Universities (Grant No. 14380046)the Program for Innovative Talents, Entrepreneur in Jiangsu。
文摘Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00076.
