Progenitor models for the "luminous" subclass of Fast Blue Optical Transients (LFBOTs; prototype: AT2018cow) are challenged to simultaneously explain all of their observed properties: fast optical rise times < days; peak luminosities >1e44 erg/s; low yields <0.1 Msun of 56Ni; aspherical ejecta with a wide velocity range (<3000 km/s to > 0.1-0.5 c with increasing polar latitude); presence of hydrogen-depleted-but-not-free dense circumstellar material (CSM) on radial scales from ~1e14 cm to ~3e16 cm; embedded variable source of non-thermal X-ray/gamma-rays, suggestive of a compact object. We show that all of these properties are consistent with the tidal disruption and hyper-accretion of a Wolf-Rayet (WR) star by a black hole (BH) or neutron star (NS) binary companion. In contrast with related previous models, the merger occurs with a long delay (>~ 100 years) following the common envelope (CE) event responsible for birthing the binary, as a result of gradual angular momentum loss to a relic circumbinary disk. Disk-wind outflows from the merger-generated accretion flow generate the 56Ni-poor aspherical ejecta with the requisite velocity range. The optical light curve is powered primarily by reprocessing X-rays from the inner accretion flow/jet, though CSM shock interaction also contributes. Primary CSM sources include mass-loss from WR star (e.g., from the L2 point) during the earliest stages of the merger (~<1e14 cm) and the relic CE disk and its photoevaporation-driven wind (>~ 1e16 cm). Longer delayed mergers may instead give rise to supernovae Type Ibn/Icn (depending on the WR evolutionary state), potentially connecting these transient classes with LFBOTs.
SN 2024abvb: a Type Ibn/Icn supernova with evidence of helium and an extreme offset from its host galaxy
Cardiff University（卡迪夫大学）；INAF-Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；European Southern Observatory（欧洲南方天文台）；Universidad de Tarapacá（塔拉帕卡大学）；University of Arizona（亚利桑那大学）；University of Hawaii at Manoa（夏威夷大学马诺阿分校）；National Central University（中央大学）；Las Cumbres Observatory（激光观测站）；University of California, Santa Barbara（加州大学圣塔芭芭拉分校）
SN 2024abvb是一种具有氦证据的Ibn/Icn型超新星，其与宿主星系存在极端偏移，光谱和光度特征显示其独特的演化模式。
Nested, asymmetric H-He circumstellar shells in the Type Icn/Ibn SN 2024abvb
European Southern Observatory（欧洲南方天文台）；Cardiff University（卡迪夫大学）；University of Ferrara（费拉拉大学）；INFN, Sezione di Ferrara（意大利国家核物理研究所费拉拉分部）；INAF, Osservatorio Astronomico d’Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；National Central University（中央大学）；University College Dublin（都柏林大学学院）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究研究所）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所）
JWST Reveals Large Reservoirs of Dust and Ongoing Circumstellar Interaction in SN Ibn/Icn 2023xgo over a Year Post-Explosion
University of California, Santa Cruz（加州大学圣克鲁兹分校）；National Astronomical Research Institute of Thailand（泰国国家天文研究所）；SETI Institute（SETI研究所）；The University of Melbourne（墨尔本大学）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；INAF, Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Space Telescope Science Institute（太空望远镜科学研究所）；Stockholm University（斯德哥尔摩大学）；Northwestern University（西北大学）
We present observations of SN 2021csp, the second example of a newly-identified type of supernova (Type Icn) hallmarked by strong, narrow, P Cygni carbon features at early times. The SN appears as a fast and luminous blue transient at early times, reaching a peak absolute magnitude of -20 within 3 days due to strong interaction between fast SN ejecta (v ~ 30000 km/s) and a massive, dense, fast-moving C/O wind shed by the WC-like progenitor months before explosion. The narrow line features disappear from the spectrum 10-20 days after explosion and are replaced by a blue continuum dominated by b…
The Enigmatic Type Icn Supernova 2024abvb Located ~22 kpc from Its Host Galaxy
The University of Melbourne（墨尔本大学）；University of California, Santa Cruz（加州大学圣克鲁兹分校）；University of Hawai’i at Manoa（夏威夷大学马诺阿分校）；The Australian National University（澳大利亚国立大学）；Kavli Institute of Cosmology Cambridge（卡弗里宇宙学剑桥研究所）；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究学院）；OzGrav, Centre for Gravitational Astrophysics, College of Science, The Australian National University（澳大利亚国立大学理学院引力天体物理中心）；ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav)（ARC引力波发现卓越中心）；Australian National Centre for the Public Awareness of Science, The Australian National University（澳大利亚国立大学公众科学意识国家中心）；Department of Astronomy, The Ohio State University（俄亥俄州立大学天文学系）
Type Ibn supernovae (SNe Ibn) are thought to be the core-collapse explosions of massive stars whose ejecta interact with He-rich circumstellar material (CSM). We report the discovery of a SN Ibn, with the longest rise-time ever observed, OGLE-2014-SN-131. We discuss the potential powering mechanisms and the progenitor nature of this peculiar stripped-envelope (SE), circumstellar-interacting SN. Optical photometry and spectroscopy were obtained with multiple telescopes including VLT, NTT, and GROND. We compare light curves and spectra with those of other known SNe Ibn and Ibc. CSM velocities ar…
We present a sample of Type Icn supernovae (SNe Icn), a newly-discovered class of transients characterized by their interaction with H- and He-poor circumstellar material (CSM). This sample is the largest collection of SNe Icn to date and includes observations of two published objects (SN 2019hgp and SN 2021csp) as well as two objects (SN 2019jc and SN 2021ckj) not yet published in the literature. The SNe Icn display a range of peak luminosities, rise times, and decline rates, as well as diverse late-time spectral features. To investigate their explosion and progenitor properties we fit their …
Context: Type Ibn supernovae are a rare class of stripped envelope supernovae interacting with a helium-rich CSM. The majority of the SNe Ibn reported display a surprising homogeneity in their fast lightcurves and starforming hosts. Aims: We present the discovery and study of SN 2020bqj (ZTF20aalrqbu), a SN Ibn with a long-duration peak plateau lasting 40 days and hosted by a faint low-mass galaxy. We aim to explain its peculiar properties using an extensive data set. Methods: We compare the evolution of SN 2020bqj with SNe Ibn from the literature. We fit the bolometric and multi-band lightcur…
We present the data and analysis of SN 2018gjx, an unusual low-luminosity transient with three distinct spectroscopic phases. Phase I shows a hot blue spectrum with signatures of ionised circumstellar material (CSM), Phase II has the appearance of broad SN features, consistent with those seen in a Type IIb supernova at maximum light, and Phase III is that of a supernova interacting with helium-rich CSM, similar to a Type Ibn supernova. This event provides an apparently rare opportunity to view the inner workings of an interacting supernova. The observed properties can be explained by the explo…
Type Ibn Supernovae (SNe Ibn) show signatures of strong interaction between the SN ejecta and hydrogen-poor circumstellar matter (CSM). Deriving the ejecta and CSM properties of SNe Ibn provides a great opportunity to study the final evolution of massive stars. In the present work, we present a light curve (LC) model for the ejecta-CSM interaction, taking into account the processes in which the high-energy photons originally created at the forward and reverse shocks are converted to the observed emission in the optical. The model is applied to a sample of SNe Ibn and `SN Ibn' rapidly evolving …
PS15dpn is a luminous rapidly rising Type Ibn supernova (SN) discovered by Pan-STARRS1 (PS1). Previous study showed that its bolometric light curve (LC) cannot be explained by the $^{56}$Ni model. In this paper, we used the $^{56}$Ni model, the magnetar model, the circumstellar interaction (CSI) model, and the CSI plus $^{56}$Ni model to fit the bolometric LC of PS15dpn. We found that the $^{56}$Ni model can fit the bolometric LC but the parameters are unrealistic, and that the magnetar model, the CSI model, and the CSI plus $^{56}$Ni model can match the data with reasonable parameters. Consid…
Because core-collapse supernovae are the explosions of massive stars, which have relatively short lifetimes, they occur almost exclusively in galaxies with active star formation. On the other hand, the Type Ibn supernova PS1-12sk exploded in an environment much more typical of thermonuclear (Type Ia) supernovae: on the outskirts of the brightest elliptical galaxy in a galaxy cluster. The lack of any obvious star formation at that location presented a challenge to models of Type Ibn supernovae as the explosions of very massive Wolf-Rayet stars. Here we present a supplementary search for star fo…
ASASSN-14ms may represent the most luminous Type Ibn supernova (SN~Ibn) ever detected, with an absolute U-band magnitude brighter than -22.0 mag and a total bolometric luminosity >1.0x10^{44} erg/s near maximum light. The early-time spectra of this SN are characterized by a blue continuum on which are superimposed narrow P~Cygni profile lines of He I, suggesting the presence of slowly moving (~1000 km/s), He-rich circumstellar material (CSM). At 1--2 months after maximum brightness, the He I line profiles become only slightly broader, with blueshifted velocities of 2000--3000 km/s, consistent …
SN 2023fyq: direct detection of a Type Ibn supernova progenitor and its multi-wavelength environmental constraints
University of Chinese Academy of Sciences（中国科学院大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿天体物理研究所）；School of Space and Earth Sciences, Beihang University（北京航空航天大学空间与地球科学学院）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；Department of Astronomy, School of Physics, Peking Unversity（北京大学物理学院天文学系）
Supernova (SN) 2021ocs was discovered in the galaxy NGC 7828 ($z = 0.01911$) within the interacting system Arp 144, and subsequently classified as a normal type-Ic SN around peak brightness. VLT/FORS2 observations in the nebular phase at 148 d reveal that the spectrum is dominated by oxygen and magnesium emission lines of different transitions and ionization states: O I, [O I], [O II], [O III], Mg I, and Mg II. Such a spectrum has no counterpart in the literature, though it bears a few features similar to those of some interacting type Ibn and Icn SNe. Additionally, SN 2021ocs showed a blue co…
Observations suggest that some massive stars experience violent and eruptive mass loss associated with significant brightening that cannot be explained by hydrostatic stellar models. This event seemingly forms dense circumstellar matter (CSM). The mechanism of eruptive mass loss has not been fully explained. We focus on the fact that the timescale of nuclear burning gets shorter than the dynamical timescale of the envelope a few years before core collapse for some massive stars. To reveal the properties of the eruptive mass loss, we investigate its relation to the energy injection at the botto…
MCA-1B (also called UIT003) is a luminous hot star in the western outskirts of M33, classified over 20yr ago with a spectral type of Ofpe/WN9 and identified then as a candidate luminous blue variable (LBV). Palomar Transient Factory data reveal that this star brightened in 2010, with a light curve resembling that of the classic LBV star AFAnd in M31. Other Ofpe/WN9 stars have erupted as LBVs, but MCA-1B was unusual because it remained hot. It showed a WN-type spectrum throughout its eruption, whereas LBVs usually get much cooler. MCA-1B showed an almost four-fold increase in bolometric luminos…
We present optical photometry and spectroscopy of the peculiar Type IIn/Ibn supernova SN2011hw. Its light curve exhibits a slower decline rate than normal SNeIbc, with a peak absolute magnitude of -19.5 (unfiltered) and a secondary peak of -18.3 mag (R). Spectra of SN2011hw are unusual compared to normal SN types, most closely resembling the spectra of SNeIbn. We center our analysis on comparing SN 2011hw to the well-studied TypeIbn SN2006jc. While the two SNe have many important similarities, the differences are quite telling: compared to SN2006jc, SN2011hw has weaker HeI and CaII lines and r…
SN~2018erx: A fast-evolving, dust-reddened Type Icn supernova with broad C II emission lines
California Institute of Technology（加州理工学院）；Stockholm University（斯德哥尔摩大学）；Liverpool John Moores University（利物浦约翰摩尔斯大学）；Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)（天体物理学跨学科探索与研究中心）；University of Minnesota（明尼苏达大学）；Columbia University（哥伦比亚大学）；Flatiron Institute（平托研究所）；Weizmann Institute of Science（魏茨曼科学研究所）
The flash-ionised SN Ibn 2025kzr: H-free CSM formed during a precursor outburst 55 days prior to explosion
DTU Space, Technical University of Denmark（丹麦技术大学空间中心）；South African Astronomical Observatory（南非天文台）；Department of Astronomy, University of Cape Town（开普敦大学天文学系）；Department of Physics, University of the Free State（自由邦大学物理系）；Department of Physics, Stellenbosch University（斯坦伦布什大学物理系）；Department of Astrophysics/IMAPP, Radboud University（拉德堡德大学天体物理学系/IMAPP）；The Inter-University Institute for Data Intensive Astronomy, University of Cape Town（开普敦大学跨大学数据密集型天文研究所）；Department of Particle Physics and Astrophysics, Weizmann Institute of Science（魏茨曼科学研究所粒子物理与天体物理系）
The transitional Type Ibn/IIn SN 2022pda, with pre-explosion outbursts and a double-peaked light curve
International Centre of Supernovae (ICESUN), Yunnan Key Laboratory of Supernova Research, Yunnan Observatories, Chinese Academy of Sciences (CAS)（中国科学院云南天文台）；INAF - Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；Graduate Institute for Advanced Studies, SOKENDAI（日本综合研究大学院大学）；National Astronomical Observatory of Japan, National Institutes of Natural Sciences（日本国立天文台）
The Environments of Luminous Fast Blue Optical Transients: Evidence for a Compact Object and Wolf-Rayet Star Merger Origin
The NSF AI Institute for Artificial Intelligence and Fundamental Interactions（美国国家科学基金会人工智能基础相互作用研究所）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；Department of Physics and Columbia Astrophysics Laboratory, Columbia University（哥伦比亚大学）；Center for Nonlinear Studies, Los Alamos National Laboratory（洛斯阿拉莫斯国家实验室）；Department of Physics & Astronomy, Louisiana State University（路易斯安那州立大学）；Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University（西北大学）
Massive stars exploding in a He-rich circumstellar medium XII. SN 2024acyl: A fast, linearly declining Type Ibn supernova with early flash-ionisation features
Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；International Centre of Supernovae, Yunnan Key Laboratory（超新星国际中心，云南省重点实验室）；INAF - Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）；Department of Astronomy, Kyoto University（京都大学天文学系）；South-Western Institute for Astronomy Research, Yunnan University（云南大学西南天文研究所）；Yunnan Key Laboratory of Survey Science, Yunnan University（云南大学云南省测绘科学重点实验室）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Electronic Science and Engineering, Chongqing University of Posts and Telecommunications（重庆邮电大学电子科学与工程学院）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；INAF - Osservatorio Astronomico d’Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）
SN 2024acyl 是一种快速、线性衰减的 Type Ibn 超新星，具有早期闪光电离特征，其光谱和光变曲线特征支持由抛射物与 CSM 交互驱动的 SN 模型。
Type Ib supernovae are bluer than Type Ic supernovae
Max Planck Institute for Astrophysics（马普天体物理研究所）；European Southern Observatory（欧洲南方天文台）；Technische Universität München（慕尼黑工业大学）；Seoul National University（首尔大学）；Tel Aviv University（特拉维夫大学）；Michigan State University（密歇根州立大学）
