A study in scarlet -- II. Spectroscopic properties of a sample of Intermediate Luminosity Red Transients
arXiv:2407.21733 · doi:10.1051/0004-6361/202451735
Abstract
We investigate the spectroscopic characteristics of Intermediate Luminosity Red Transients (ILRTs), a class of elusive objects with peak luminosity between that of classical novae and standard supernovae. We present the extensive optical and near-infrared (NIR) spectroscopic monitoring of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd and AT 2019udc. First we focus on the evolution of the most prominent spectral features observed in the low resolution spectra, then we discuss more in detail the high resolution spectrum collected for NGC 300 2008OT-1 with the Very Large Telescope equipped with UVES. Finally we analyse late time spectra of NGC 300 2008OT-1 and AT 2019ahd through comparisons with both synthetic and observed spectra. Balmer and Ca lines dominate the optical spectra, revealing the presence of slowly moving circumstellar medium (CSM) around the objects. The line luminosity of H, H and Ca II NIR triplet presents a double peaked evolution with time, possibly indicative of interaction between fast ejecta and the slow CSM. The high resolution spectrum of NGC 300 2008OT-1 reveals a complex circumstellar environment, with the transient being surrounded by a slow (30 km s) progenitor wind. At late epochs, optical spectra of NGC 300 2008OT-1 and AT 2019ahd show broad (2500 km s) emission features at 6170 A and 7000 A which are unprecedented for ILRTs. We find that these lines originate most likely from the blending of several narrow lines, possibly of iron-peak elements.
arXiv comment28 pages, 19 figures. Submitted to A&A
References in corpus (51)
- X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
- Explosions of O-Ne-Mg Cores, the Crab Supernova, and Subluminous Type II-P Supernovae
- V1309 Scorpii: merger of a contact binary
- Detection of circumstellar material in a normal Type Ia Supernova
- PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
- Caltech Core-Collapse Project (CCCP) observations of type IIn supernovae: typical properties and implications for their progenitor stars
- Evidence for Asphericity in the Type IIn Supernova 1998S
- High Density Circumstellar Interaction in the Luminous Type IIn SN 2010jl: The first 1100 days
- SN 2005cs in M51 II. Complete Evolution in the Optical and the Near-Infrared
- A New Class of Luminous Transients and A First Census of Their Massive Stellar Progenitors
- Carnegie Supernova Project: Observations of Type IIn supernovae
- SN 2008S: an electron capture SN from a super-AGB progenitor?
- Nucleosynthesis in Electron Capture Supernovae of AGB Stars
- Spectral Evolution of the Extraordinary Type IIn Supernova 2006gy
- An unusually brilliant transient in the galaxy Messier 85
- Interacting Supernovae: Types IIn and Ibn
- The 2008 Luminous Optical Transient in the Nearby Galaxy NGC 300
- Optical and Ultraviolet Spectroscopy of SN 1995N: Evidence for Strong Circumstellar Interaction
- An Intermediate Luminosity Transient in NGC300: The Eruption of a Dust-Enshrouded Massive Star
- Fallback Supernovae: A Possible Origin of Peculiar Supernovae with Extremely Low Explosion Energies
- Luminous Red Novae: Stellar Mergers or Giant Eruptions?
- EC-SNe from super-AGB progenitors: theoretical models vs. observations
- The electron-capture origin of supernova 2018zd
- OGLE-2002-BLG-360: from a gravitational microlensing candidate to an overlooked red transient
- From Discovery to the First Month of the Type II Supernova 2023ixf: High and Variable Mass Loss in the Final Year before Explosion
- A very faint core-collapse supernova in M85
- Models of interacting supernovae and their spectral diversity
- Spectra of supernovae in the nebular phase
- Almost Gone: SN~2008S and NGC~300 2008OT-1 are Fainter than their Progenitors
- NGC 300 OT2008-1 As a Scaled-Down Version of the Eta Carinae Great Eruption
- Supernova Impostors and other Gap Transients
- The Photometric and Spectral Evolution of the 2008 Luminous Optical Transient in NGC 300
- Post-outburst spectra of a stellar-merger remnant of V1309 Scorpii: from a twin of V838 Monocerotis to a clone of V4332 Sagittarii
- Atomic data from the Iron Project. LXIV. Radiative transition rates and collision strengths for Ca II
- The long-lived Type IIn SN 2015da: Infrared echoes and strong interaction within an extended massive shell
- New Observations of the Very Luminous Supernova 2006gy: Evidence for Echoes
- Electron scattering wings on lines in interacting supernovae
- VLT Spectropolarimetry of the optical transient in NGC300. Evidence for asymmetry in the circumstellar dust
- The Carnegie Supernova Project II. The shock wave revealed through the fog: The strongly interacting Type IIn SN 2013L
- Volumetric rates of Luminous Red Novae and Intermediate Luminosity Red Transients with the Zwicky Transient Facility
- Luminous Red Nova 2015 in the Galaxy M101
- The Carnegie Supernova Project II. Observations of the intermediate luminosity red transient SNhunt120
- Gap Transients Interacting with Circumstellar Medium
- Intermediate Luminosity Red Transients by Black Holes Born from Erupting Massive Stars
- SN 2021foa, a transitional event between a Type IIn (SN 2009ip-like) and a Type Ibn supernova
- Explaining recently studied intermediate luminosity optical transients (ILOTs) with jet powering
- Panchromatic evolution of three luminous red novae: Forbidden hugs in pandemic times -- IV
- Revisiting V1309 Sco 2008 outburst spectra. Observational evidence for theoretical modeling of stellar mergers
- The O I] 1641A line as a probe of symbiotic star winds
- Time varying Na I D absorption in ILRTs as a probe of circumstellar material
- A study in scarlet -- I. Photometric properties of a sample of Intermediate Luminosity Red Transients