A star completely destroyed in a tidal disruption event (TDE) ignites a luminous flare that is powered by the fallback of tidally stripped debris to a supermassive black hole (SMBH) of mass
The presence of magnetic fields in the late inspiral of black hole–neutron star binaries could lead to potentially detectable electromagnetic precursor transients. Using generalrelativistic forcefree electrodynamics simulations, we investigate premerger interactions of the common magnetosphere of black hole–neutron star systems. We demonstrate that these systems can feature copious electromagnetic flaring activity, which we find depends on the magnetic field orientation but not on black hole spin. Due to interactions with the surrounding magnetosphere, these flares could lead to fastradioburstlike transients and Xray emission, with
 NSFPAR ID:
 10469384
 Publisher / Repository:
 DOI PREFIX: 10.3847
 Date Published:
 Journal Name:
 The Astrophysical Journal Letters
 Volume:
 956
 Issue:
 2
 ISSN:
 20418205
 Format(s):
 Medium: X Size: Article No. L33
 Size(s):
 ["Article No. L33"]
 Sponsoring Org:
 National Science Foundation
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Abstract M _{•}. We analyze two estimates for the peak fallback rate in a TDE, one being the “frozenin” model, which predicts a strong dependence of the time to peak fallback rate,t _{peak}, on both stellar mass and age, with 15 days ≲t _{peak}≲ 10 yr for main sequence stars with masses 0.2 ≤M _{⋆}/M _{⊙}≤ 5 andM _{•}= 10^{6}M _{⊙}. The second estimate, which postulates that the star is completely destroyed when tides dominate the maximum stellar selfgravity, predicts thatt _{peak}is very weakly dependent on stellar type, with for 0.2 ≤ ${t}_{\mathrm{peak}}=\left(23.2\pm 4.0\phantom{\rule{0.25em}{0ex}}\mathrm{days}\right){\left({M}_{\u2022}/{10}^{6}{M}_{\odot}\right)}^{1/2}$M _{⋆}/M _{⊙}≤ 5, while for a Kroupa initial mass function truncated at 1.5 ${t}_{\mathrm{peak}}\phantom{\rule{0.25em}{0ex}}=\left(29.8\pm 3.6\phantom{\rule{0.25em}{0ex}}\mathrm{days}\right){\left({M}_{\u2022}/{10}^{6}{M}_{\odot}\right)}^{1/2}$M _{⊙}. This second estimate also agrees closely with hydrodynamical simulations, while the frozenin model is discrepant by orders of magnitude. We conclude that (1) the time to peak luminosity in complete TDEs is almost exclusively determined by SMBH mass, and (2) massivestar TDEs power the largest accretion luminosities. Consequently, (a) decadeslong extragalactic outbursts cannot be powered by complete TDEs, including massivestar disruptions, and (b) the most highly superEddington TDEs are powered by the complete disruption of massive stars, which—if responsible for producing jetted TDEs—would explain the rarity of jetted TDEs and their preference for young and starforming host galaxies. 
Abstract We present a detection of 21 cm emission from largescale structure (LSS) between redshift 0.78 and 1.43 made with the Canadian Hydrogen Intensity Mapping Experiment. Radio observations acquired over 102 nights are used to construct maps that are foreground filtered and stacked on the angular and spectral locations of luminous red galaxies (LRGs), emissionline galaxies (ELGs), and quasars (QSOs) from the eBOSS clustering catalogs. We find decisive evidence for a detection when stacking on all three tracers of LSS, with the logarithm of the Bayes factor equal to 18.9 (LRG), 10.8 (ELG), and 56.3 (QSO). An alternative frequentist interpretation, based on the likelihood ratio test, yields a detection significance of 7.1
σ (LRG), 5.7σ (ELG), and 11.1σ (QSO). These are the first 21 cm intensity mapping measurements made with an interferometer. We constrain the effective clustering amplitude of neutral hydrogen (Hi ), defined as , where Ω_{Hi}is the cosmic abundance of H ${\mathit{\ue22d}}_{\mathrm{H}\phantom{\rule{0.25em}{0ex}}\mathrm{I}}\equiv {10}^{3}\phantom{\rule{0.25em}{0ex}}{\mathrm{\Omega}}_{\mathrm{H}\phantom{\rule{0.25em}{0ex}}\mathrm{I}}\left({b}_{\mathrm{H}\phantom{\rule{0.25em}{0ex}}\mathrm{I}}+\u3008\phantom{\rule{0.25em}{0ex}}f{\mu}^{2}\u3009\right)$i ,b _{Hi}is the linear bias of Hi , and 〈f μ ^{2}〉 = 0.552 encodes the effect of redshiftspace distortions at linear order. We find for LRGs ( ${\mathit{\ue22d}}_{\mathrm{H}\phantom{\rule{0.25em}{0ex}}\mathrm{I}}={1.51}_{0.97}^{+3.60}$z = 0.84), for ELGs ( ${\mathit{\ue22d}}_{\mathrm{H}\phantom{\rule{0.25em}{0ex}}\mathrm{I}}={6.76}_{3.79}^{+9.04}$z = 0.96), and for QSOs ( ${\mathit{\ue22d}}_{\mathrm{H}\phantom{\rule{0.25em}{0ex}}\mathrm{I}}={1.68}_{0.67}^{+1.10}$z = 1.20), with constraints limited by modeling uncertainties at nonlinear scales. We are also sensitive to bias in the spectroscopic redshifts of each tracer, and we find a nonzero bias Δv = − 66 ± 20 km s^{−1}for the QSOs. We split the QSO catalog into three redshift bins and have a decisive detection in each, with the upper bin atz = 1.30 producing the highestredshift 21 cm intensity mapping measurement thus far. 
Abstract We investigate the stellar mass–black hole mass (
) relation with type 1 active galactic nuclei (AGNs) down to ${\mathit{\ue239}}_{*}\u2013{\mathit{\ue239}}_{\mathrm{BH}}$ , corresponding to a ≃ −21 absolute magnitude in restframe ultraviolet, at ${\mathit{\ue239}}_{\mathrm{BH}}={10}^{7\phantom{\rule{0.11em}{0ex}}}{M}_{\odot}$z = 2–2.5. Exploiting the deep and largearea spectroscopic survey of the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX), we identify 66 type 1 AGNs with ranging from 10^{7}–10^{10} ${\mathit{\ue239}}_{\mathrm{BH}}$M _{⊙}that are measured with singleepoch virial method using Civ emission lines detected in the HETDEX spectra. of the host galaxies are estimated from optical to nearinfrared photometric data taken with Spitzer, the Widefield Infrared Survey Explorer, and groundbased 4–8 m class telescopes by ${\mathit{\ue239}}_{*}$CIGALE spectral energy distribution (SED) fitting. We further assess the validity of SED fitting in two cases by hostnuclear decomposition performed through surface brightness profile fitting on spatially resolved host galaxies with the James Webb Space Telescope/NIRCam CEERS data. We obtain the relation covering the unexplored lowmass ranges of ${\mathit{\ue239}}_{*}\u2013{\mathit{\ue239}}_{\mathrm{BH}}$ , and conduct forward modeling to fully account for the selection biases and observational uncertainties. The intrinsic ${\mathit{\ue239}}_{\mathrm{BH}}\phantom{\rule{0.25em}{0ex}}\sim \phantom{\rule{0.25em}{0ex}}{10}^{7}\u2013{10}^{8}\phantom{\rule{0.25em}{0ex}}{M}_{\odot}$ relation at ${\mathit{\ue239}}_{*}\u2013{\mathit{\ue239}}_{\mathrm{BH}}$z ∼ 2 has a moderate positive offset of 0.52 ± 0.14 dex from the local relation, suggestive of more efficient black hole growth at higher redshift even in the lowmass regime of . Our ${\mathit{\ue239}}_{\mathrm{BH}}\phantom{\rule{0.25em}{0ex}}\sim \phantom{\rule{0.25em}{0ex}}{10}^{7}\u2013{10}^{8}\phantom{\rule{0.25em}{0ex}}{M}_{\odot}$ relation is inconsistent with the ${\mathit{\ue239}}_{*}\u2013{\mathit{\ue239}}_{\mathrm{BH}}$ suppression at the low ${\mathit{\ue239}}_{\mathrm{BH}}$ regime predicted by recent hydrodynamic simulations at a 98% confidence level, suggesting that feedback in the lowmass systems may be weaker than those produced in hydrodynamic simulations. ${\mathit{\ue239}}_{*}$ 
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