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Identification of Single Spectral Lines in Large Spectroscopic Surveys Using UMLAUT: an Unsupervised Machine-learning Algorithm Based on Unbiased Topology
Rodighiero, G.; Vaccari, M.; Battisti, A. +19 more
The identification of an emission line is unambiguous when multiple spectral features are clearly visible in the same spectrum. However, in many cases, only one line is detected, making it difficult to correctly determine the redshift. We developed a freely available unsupervised machine-learning algorithm based on unbiased topology (UMLAUT) that …
Analysis of Type II and Type III Radio Bursts Associated with SEPs from Non-Interacting/Interacting Radio-Loud CMEs
Feng, Li; Prakash, O.; Shanmugaraju, A. +4 more
We analyze radio bursts observed in events with interacting/non-interacting CMEs that produced major SEPs (Ip > 10 MeV) from April 1997 to December 2014. We compare properties of meter (m), decahectometer (DH) type II and DH type III bursts, and time lags for interacting-CME-associated (IC) events and non-interacting-CME-associated (…
Morphological Transformation and Star Formation Quenching of Massive Galaxies at 0.5 ≤ z ≤ 2.5 in 3D-HST/CANDELS
Fang, Guanwen; Gu, Yizhou; Yuan, Qirong +4 more
To figure out the effect of stellar mass and local environment on morphological transformation and star formation quenching in galaxies, we use the massive (M * ≥ 1010 M ⊙) galaxies at 0.5 ≤ z ≤ 2.5 in five fields of 3D-HST/CANDELS. Based on the UVJ diagnosis and the possibility of possessing a spheroid, our sample…
SP_Ace v1.4 and the new GCOG library for deriving stellar parameters and elemental abundances
Vallenari, A.; Lucatello, S.; Boeche, C.
Context. Ongoing and future massive spectroscopic surveys will collect very large numbers (106-107) of stellar spectra that need to be analyzed. Highly automated software is needed to derive stellar parameters and chemical abundances from these spectra.
Aims: We present the new version of SP_Ace (Stellar Parameters And C…
The nuclear environment of NGC 2442: a Compton-thick low-luminosity AGN
Steiner, J. E.; Menezes, R. B.; da Silva, Patrícia +2 more
The detailed study of nuclear regions of galaxies is important because it can help understanding the active galactic nucleus (AGN) feedback mechanisms, the connections between the nuclei and their host galaxies, and ultimately the galaxy formation processes. We present the analysis of an optical data cube of the central region of the galaxy NGC 24…
The Young Stellar Population, Distance, and Cloud-Cloud Collision Induced Star Formation Scenario of the Trifid Nebula
Kalari, Venu M.
The Trifid Nebula is a young, nearby star-forming region where star formation is proposed to have been triggered by cloud-cloud collision (CCC), based on observations of molecular clouds. It offers a unique opportunity to test whether the CCC hypothesis is supported by the spatial distribution and star formation chronology of young stars. We prese…
Segmentation of Coronal Features to Understand the Solar EUV and UV Irradiance Variability III. Inclusion and Analysis of Bright Points
Giono, Gabriel; van der Zwaard, Rens; Kariyappa, Rangaiah +3 more
The study of solar irradiance variability is of great importance in heliophysics, Earth's climate, and space weather applications. These studies require careful identifying, tracking and monitoring of features in the solar photosphere, chromosphere, and corona. Do coronal bright points contribute to the solar irradiance or its variability as input…
Low-redshift Type Ia Supernova from the LSQ/LCO Collaboration
Howell, D. A.; McCully, C.; Baltay, C. +16 more
This paper is the data release of a new sample of 140 type Ia supernovae (SNe Ia) from the LaSilla-QUEST/Las Cumbres Observatory (LCO) collaboration. The discovery of the supernovae came from the LaSilla-QUEST variability survey, the ASASSN survey, as well as smaller low redshift supernova surveys. All of the supernovae in this sample were spectro…
Detection of an energetic flare from the M5V secondary star in the Polar MQ Dra
Ramsay, Gavin; Hakala, Pasi; Wood, Matt A.
MQ Dra is a strongly magnetic Cataclysmic Variable whose white dwarf accretes material from its secondary star through a stellar wind at a low rate. TESS observations were made of MQ Dra in four sectors in Cycle 2 and show a short duration, high energy flare (~1035 erg) which has a profile characteristic of a flare from the M5V secondar…
A VLA Survey of Late-time Radio Emission from Superluminous Supernovae and the Host Galaxies
Tamura, Yoichi; Tominaga, Nozomu; Hatsukade, Bunyo +5 more
We present the results of 3 GHz radio continuum observations of 23 superluminous supernovae (SLSNe) and their host galaxies by using the Karl G. Jansky Very Large Array conducted 5-21 yr after the explosions. The sample consists of 15 Type I and 8 Type II SLSNe at z < 0.3, providing one of the largest samples of SLSNe with late-time radio data.…