Pulsars, transients and relativistic astrophysics

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The 2019 outburst of the 2005 classical nova V1047 Cen: a record breaking dwarf nova outburst or a new phenomenon?

(2021)

Authors:

E Aydi, KV Sokolovsky, JS Bright, E Tremou, MM Nyamai, A Evans, J Strader, L Chomiuk, G Myers, F-J Hambsch, KL Page, DAH Buckley, CE Woodward, FM Walter, P Mr贸z, PJ Vallely, TR Geballe, DPK Banerjee, RD Gehrz, RP Fender, M Gromadzki, A Kawash, C Knigge, K Mukai, U Munari, M Orio, VARM Ribeiro, JL Sokoloski, S Starrfield, A Udalski, PA Woudt

SN2017jgh - A high-cadence complete shock cooling lightcurve of a SN IIb with the Kepler telescope

(2021)

Authors:

P Armstrong, BE Tucker, A Rest, R Ridden-Harper, Y Zenati, AL Piro, S Hinton, C Lidman, S Margheim, G Narayan, E Shaya, P Garnavich, D Kasen, V Villar, A Zenteno, I Arcavi, M Drout, RJ Foley, J Wheeler, J Anais, A Campillay, D Coulter, G Dimitriadis, D Jones, CD Kilpatrick, N Mu帽oz-Elgueta, C Rojas-Bravo, J Vargas-Gonz谩lez, J Bulger, K Chambers, M Huber, T Lowe, E Magnier, BJ Shappee, S Smartt, KW Smith, T Barclay, G Barentsen, J Dotson, M Gully-Santiago, C Hedges, S Howell, A Cody, K Auchettl, A B贸di, Zs Bogn谩r, J Brimacombe, P Brown, B Cseh, L Galbany, D Hiramatsu, TW-S Holoien, DA Howell, SW Jha, R K枚nyves-T贸th, L Kriskovics, C McCully, P Milne, J Mu帽oz, Y Pan, A P谩l, H Sai, K S谩rneczky, N Smith, 脕 S贸dor, R Szab贸, R Szak谩ts, S Valenti, J Vink贸, X Wang, K Zhang, G Zsidi

Signatures of hierarchical mergers in black hole spin and mass distribution

Monthly Notices of the Royal Astronomical Society Oxford University Press 507:3 (2021) 3362-3380

Authors:

Hiromichi Tagawa, Zoltan Haiman, Imre Bartos, Bence Kocsis, Kazuyuki Omukai

Abstract:

Recent gravitational wave (GW) observations by LIGO/Virgo show evidence for hierarchical mergers, where the merging BHs are the remnants of previous BH merger events. These events may carry important clues about the astrophysical host environments of the GW sources. In this paper, we present the distributions of the effective spin parameter (蠂eff), the precession spin parameter (蠂p), and the chirp mass (mchirp) expected in hierarchical mergers. Under a wide range of assumptions, hierarchical mergers produce (i) a monotonic increase of the average of the typical total spin for merging binaries, which we characterize with 蠂炉typ鈮(蠂2eff+蠂2p)1/2鈦, up to roughly the maximum mchirp among first-generation (1g) BHs, and (ii) a plateau at 蠂炉typ鈭0.6 at higher mchirp. We suggest that the maximum mass and typical spin magnitudes for 1g BHs can be estimated from 蠂炉typ as a function of mchirp. The GW data observed in LIGO/Virgo O1鈥揙3a prefers an increase in 蠂炉typ at low mchirp, which is consistent with the growth of the BH spin magnitude by hierarchical mergers at 鈭2蟽 confidence. A Bayesian analysis using the 蠂eff, 蠂p, and mchirp distributions suggests that 1g BHs have the maximum mass of 鈭15鈥30M鈯 if the majority of mergers are of high-generation BHs (not among 1g鈥1g BHs), which is consistent with mergers in active galactic nucleus discs and/or nuclear star clusters, while if mergers mainly originate from globular clusters, 1g BHs are favoured to have non-zero spin magnitudes of 鈭0.3. We also forecast that signatures for hierarchical mergers in the 蠂炉typ distribution can be confidently recovered once the number of GW events increases to 鈮 O(100).

Intermediate-luminosity red transients: Spectrophotometric properties and connection to electron-capture supernova explosions

(2021)

Authors:

Y-Z Cai, A Pastorello, M Fraser, MT Botticella, N Elias-Rosa, L-Z Wang, R Kotak, S Benetti, E Cappellaro, M Turatto, A Reguitti, S Mattila, SJ Smartt, C Ashall, S Benitez, T-W Chen, A Harutyunyan, E Kankare, P Lundqvist, PA Mazzali, A Morales-Garoffolo, P Ochner, G Pignata, SJ Prentice, TM Reynolds, X-W Shu, MD Stritzinger, L Tartaglia, G Terreran, L Tomasella, S Valenti, G Valerin, G-J Wang, X-F Wang, L Borsato, E Callis, G Cannizzaro, S Chen, E Congiu, M Ergon, L Galbany, A Gal-Yam, X Gao, M Gromadzki, S Holmbo, F Huang, C Inserra, K Itagaki, Z Kostrzewa-Rutkowska, K Maguire, S Margheim, S Moran, F Onori, A Sagu茅s Carracedo, KW Smith, J Sollerman, A Somero, B Wang, DR Young

Southern African Large Telescope Spectroscopy of BL Lacs for the CTA project

(2021)

Authors:

E Kasai, P Goldoni, M Backes, G Cotter, S Pita, C Boisson, DA Williams, F D'Ammando, E Lindfors, U Barres de Almeida, W Max-Moerbeck, V Navarro-Aranguiz, J Becerra-Gonzalez, O Hervet, J-P Lenain, H Sol, S Wagner