scholarly journals Lα Radiation and CaII Ionization in the TYPE II Supernovae at Late Times

1988 ◽  
Vol 108 ◽  
pp. 415-416
Author(s):  
Nikolai N. Chugai
Keyword(s):  
Emission Lines ◽  
Type Ii ◽  
Order Of Magnitude

AbstractThe ionization of CaII by the Lα quanta in the envelope of the type II supernova 1970g on 270th day is considered. The ratio CaII/CaIII is found to be very low (<0.1). This results in the low theoretical intensities of the CaII emission lines; they are at least an order of magnitude weaker than the observed ones. The implications are discussed.

scholarly journals GRO J1744-28 and the Rapid Burster; Bizarre Objects!

1998 ◽  
Vol 188 ◽  
pp. 111-111
Author(s):  
Walter H.G. Lewin
Keyword(s):  
Type Ii ◽  
Time Intervals ◽  
Periodic Oscillations ◽  
X Ray ◽  
Magnetic Dipole Field ◽  
Order Of Magnitude ◽  
Low Mass ◽  
Type Ii Bursts ◽  
The Difference ◽  
X Ray Binaries

The bursts from GRO J1744-28 are due to accretion instabilities as is the case for type II bursts in the Rapid Burster. Both sources are transient Low-Mass X-ray Binaries, and they both exhibit unusual quasi-periodic-oscillations in their persistent X-ray flux following several (not all) of the type II bursts. There are important differences too. GRO J1744-28 is an X-ray pulsar; the Rapid Burster is not. In addition, the pattern of bursts and the burst peak luminosities are very different for the two sources. Time intervals between the rapidly repetitive bursts in the Rapid Burster can be as short as 10 sec, in 1744-28 they are as short as 200 sec. The peak luminosities of the bursts from GRO J1744-28 can exceed the Eddington luminosity (for assumed isotropic emission) by one to two orders of magnitude. The QPO centroid frequencies (see above) differ by an order of magnitude (~0.04 Hz for the Rapid Burster, and 0.3 Hz for GRO J1744-28). The difference in behavior p obably lies in the difference in the magnetic dipole field strength of the accreting neutron stars (for GRO J1744-28 it is almost certainly much higher than for the Rapid Burster). It remains puzzling, why GRO J1744-28 and the Rapid Burster are the only known sources which exhibit rapidly repetitive type II bursts.

scholarly journals Late-time Spectral Observations of Type IIP Supernovae

2015 ◽  
Vol 11 (A29B) ◽  
pp. 472-472
Author(s):  
Jeffrey M. Silverman ◽  
Stephanie Pickett ◽  
J. Craig Wheeler ◽  
Alexei V. Filippenko
Keyword(s):  
Temporal Evolution ◽  
Optical Spectra ◽  
Photometric Data ◽  
Emission Lines ◽  
Late Time ◽  
Type Ii ◽  
Insight Into

We are analysing late-time (older than about 150 d past explosion) optical spectra of Type II-Plateau (IIP) supernovae (SNe), which are H-rich SNe that come from red supergiant (RSG) progenitors. The dataset includes nearly 100 spectra of about 40 objects, making this the largest sample of SN IIP nebular spectra ever investigated. Quantitative criteria from within the spectra themselves are employed to determine if an observation is truly nebular, and thus should be included in the study. We present the temporal evolution of the fluxes, shapes, and velocities of various emission lines (see, for example, Fig. 1). These measured values are also compared to photometric data in order to search for correlations that can allow us to gain insight into the diversity of RSG progenitors and learn more about the details of the explosion itself.

scholarly journals Carbon-loud SDSS BOSS type II quasars at z > 2: high-density gas or secondary production of carbon?

2020 ◽  
Vol 495 (4) ◽  
pp. 4707-4746
Author(s):  
M Silva ◽  
A Humphrey ◽  
P Lagos ◽  
S G Morais
Keyword(s):  
Abundance Ratio ◽  
Systematic Difference ◽  
Sloan Digital Sky Survey ◽  
Type Ii ◽  
Narrow Line ◽  
Chemical Abundances ◽  
Gas Density ◽  
Chemical Enrichment ◽  
Order Of Magnitude ◽  
Nitrogen Abundance

ABSTRACT We study the ultraviolet (UV) emission-line ratios of a sample of 145 type II quasars (QSO2s) from Sloan Digital Sky Survey iii Baryon Oscillation Spectroscopic Survey, and compare against a grid of active galactic nucleus (AGN) photoionization models with a range in gas density, gas chemical abundances, and ionization parameter. Most of the quasars are ‘carbon-loud’, with C  iv/He ii ratios that are unusually high for the narrow-line region, implying higher than expected gas density (&gt;106 cm−3) and/or significantly supersolar-relative carbon abundance. We also find that solar or supersolar nitrogen abundance and metallicity are required in the majority of our sample, with potentially significant variation between objects. Compared to radio galaxies at similar redshifts (HzRGs; z &gt; 2), the QSO2s are offset to higher N  v/He ii, C  iv/He ii, and C iii]/He ii, suggesting systematically higher gas density and/or systematically higher C and N abundances. We find no evidence for a systematic difference in the N/C abundance ratio between the two types of objects. Scatter in the N  iv]/C  iv ratio implies a significant scatter in the N/C abundance ratio among the QSO2s and HzRGs, consistent with differences in the chemical enrichment histories between objects. Interestingly, we find that adopting secondary behaviour for both N and C alleviates the long-standing ‘N  iv] problem’. A subset of the QSO2s and HzRGs also appear to be ‘silicon-loud’, with Si iii] relative fluxes suggesting Si/C and Si/O are an order of magnitude above their solar values. Finally, we propose new UV-line criteria to select genuine QSO2s with low-density narrow-line regions.

Compare the Petrophysics of Formation Type I and II by Mercury Injection Curve Normalization

2014 ◽  
Vol 960-961 ◽  
pp. 258-261
Author(s):  
Ling Yun Chen ◽  
Yi Kun Liu ◽  
Li Hua Xia ◽  
Qian Liu
Keyword(s):  
Capillary Pressure ◽  
Thin Layers ◽  
Type I ◽  
Type Ii ◽  
Visual Identification ◽  
Mercury Injection ◽  
Order Of Magnitude ◽  
Formation Type ◽  
Capillary Pressure Curves ◽  
Developing Method

Study on Formation Type II is so few that affect on tapping the potential [2]. Analyzing petrophysics of Formation Type I and II by mercury injection curve normalization, it’s vital to developing method choice on tapping the potential of Formation Type II. Capillary pressure curves (Pc-curves) from conventional Mercury Injection are hard to analyze and compare because of various shapes. To get typical capillary pressure curves for Formation Type I and II, the curves from Mercury Injection is processed by Function J, and the J function curves and normalized Pc-curves for tabulated thin layers, tabulated thick layers and un-tabulated layers in Formation Type I and II, compare and analyze the influence of permeability on the shape of J function curves and normalized Pc-curves; compare the influence of different kinds of layers with the same permeability order of magnitude on the shape of J function curves and normalized Pc-curves, i.e. the influence of other factors except permeability, to get some visual identification methods and analyze the petrophysics difference between Formation Type I and II which is shown on Pc-curves.

scholarly journals FLASH SPECTROSCOPY: EMISSION LINES FROM THE IONIZED CIRCUMSTELLAR MATERIAL AROUND <10-DAY-OLD TYPE II SUPERNOVAE

2016 ◽  
Vol 818 (1) ◽  
pp. 3 ◽  
Author(s):  
D. Khazov ◽  
O. Yaron ◽  
A. Gal-Yam ◽  
I. Manulis ◽  
A. Rubin ◽  
...  
Keyword(s):  
Emission Lines ◽  
Type Ii ◽  
Circumstellar Material ◽  
Flash Spectroscopy

scholarly journals A Study of Dense Molecular Gas and Star Formation toward the Vela Molecular Ridge with NANTEN

1999 ◽  
Vol 51 (6) ◽  
pp. 775-790 ◽  
Author(s):  
Nobuyuki Yamaguchi ◽  
Norikazu Mizuno ◽  
Hiro Saito ◽  
Ken'ichi Matsunaga ◽  
Akira Mizuno ◽  
...  
Keyword(s):  
Star Formation ◽  
Total Mass ◽  
Massive Stars ◽  
Emission Lines ◽  
Molecular Gas ◽  
H Ii Regions ◽  
Molecular Outflow ◽  
Total Luminosity ◽  
Preceding Work ◽  
Order Of Magnitude

Abstract New observations of the J=1−0 12CO, 13CO, and C18O emission lines have been extensively made toward the Vela Molecular Ridge (VMR) with NANTEN. The most prominent cloud is the giant molecular cloud, corresponding to the VMR-C region (Vela C). The present C18O distribution has been identified as 29 clouds. Among them, the most massive one is included in Vela C, having a total mass of ∼ 4.4 × 104M⊙. The rest of them are smaller C18O clouds of 102-103M⊙. Star formation in the region is almost exclusively occurring in the C18O clouds. The luminosities of the associated protostellar IRAS sources range from 5 L⊙ to 1.1 × 104L⊙, and the luminosity distribution is found to be well represented by the relation dNstar/dLIR ∞ L-1.65±0.14IR. We find that the ratios of the total luminosity of the sources associated with given C18O clouds to the cloud masses are significantly enhanced for those clouds associated with H II regions by an order of magnitude. This is interpreted as meaning that the formation of massive stars is enhanced due to the effects of H II regions, as is consistent with the preceding work. We have also newly found molecular outflow toward IRAS 08588–4347 as well as five possible candidates for outflows.

Crystallographic insights into Ni–Co–Mn–In metamagnetic shape memory alloys

2016 ◽  
Vol 49 (5) ◽  
pp. 1585-1592 ◽  
Author(s):  
Haile Yan ◽  
Chunyang Zhang ◽  
Yudong Zhang ◽  
Xinli Wang ◽  
Claude Esling ◽  
...  
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Electron Backscatter Diffraction ◽  
Atomic Scale ◽  
Type I ◽  
Angular Deviation ◽  
Type Ii ◽  
Twin Interface ◽  
Transmission Electron ◽  
Order Of Magnitude

In the present work, the morphological and crystallographic features of the 6M modulated martensite in the Ni45Co5Mn37In13 alloy were investigated by electron backscatter diffraction and high-resolution transmission electron microscopy (HRTEM) at room temperature. The 6M modulated martensite is in plate form and organized in colonies within which the plates stretch roughly in the same direction. Each colony has four types of orientation variants that are related to three kinds of twin relations, i.e. \{ 1 \bar 2\bar 3\} _{\rm M} type I, \langle \bar 3\bar 3{{1}} \rangle _{\rm M} type II and {{\{ 103\} }}_{\rm M} compound twins. The twinning shears of type I and type II twins are the same and equal to 0.2681, being about one order of magnitude higher than that of the compound twin (0.0330). Variant interfaces are microscopically defined by their corresponding twinning plane K 1. The HRTEM investigations show that the interfaces of the type I twin are straight and coherent at atomic scale, whereas those of the type II and compound twins are `stepped'. The step height of the compound twin interfaces is much larger than that of the type II twin interfaces. In view of variant organization, there is only one oriented type I interface and one compound twin interface, but there are two oriented type II interfaces which have an angular deviation of ±5.32° with respect to the type I twin interface. The results of the present work provide comprehensive information on morphological and crystallographic features of Ni–Co–Mn–In metamagnetic shape memory alloys.

scholarly journals A progenitor candidate for the type II-P supernova SN 2018aoq in NGC 4151

2019 ◽  
Vol 622 ◽  
pp. L1 ◽  
Author(s):  
D. O’Neill ◽  
R. Kotak ◽  
M. Fraser ◽  
S. A. Sim ◽  
S. Benetti ◽  
...  
Keyword(s):  
Binary Star ◽  
Spectral Energy Distribution ◽  
Absolute Magnitude ◽  
Spectral Energy ◽  
Type Ii ◽  
Imaging Data ◽  
Ngc 4151 ◽  
Star Models ◽  
Order Of Magnitude ◽  
Good Agreement

We present our findings based on pre- and post-explosion data of the type II-Plateau SN 2018aoq that exploded in NGC 4151. As distance estimates to NGC 4151 vary by an order of magnitude, we utilised the well-known correlation between ejecta velocity and plateau brightness, i.e. the standard candle method, to obtain a distance of 18.2 ± 1.2 Mpc, which is in very good agreement with measurements based on geometric methods. The above distance implies a mid-plateau absolute magnitude of MV50 = − 15.76 ± 0.14 suggesting that it is of intermediate brightness when compared to IIP SNe such as SN 2005cs at the faint end, and more typical events such as SN 1999em. This is further supported by relatively low expansion velocities (Fe IIλ5169 ∼ 3000 km s−1 at +42 d). Using archival HST/WFC3 imaging data, we find a point source coincident with the supernova position in the F350LP, F555W, F814W, and F160W filters. This source shows no significant variability over the ∼2 month time span of the data. From fits to the spectral energy distribution of the candidate progenitor, we find log(L/L⊙) ∼ 4.7 and Teff ∼ 3.5 kK, implying an M-type red supergiant progenitor. From comparisons to single and binary star models, we find that both favour the explosion of a star with a zero-age main sequence mass of ∼10 M⊙.

MAGNETO-LUMINESCENCE OF A SINGLE LATERAL ISLAND FORMED IN A TYPE - II GaAs/AlAs QW

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3807-3812 ◽  
Author(s):  
BARBARA CHWALISZ ◽  
ANDRZEJ WYSMOLEK ◽  
ROMAN STȨPNIEWSKI ◽  
ADAM BABINSKI ◽  
MAREK POTEMSKI ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Emission Lines ◽  
Luminescence Spectra ◽  
Double Quantum ◽  
Type I ◽  
Type Ii ◽  
Quantum Well Structures ◽  
Indirect Excitons ◽  
Double Quantum Well ◽  
Efficient Type

Ensembles of sharp emission lines present in the macro-luminescence of type-II GaAs / AlAs double quantum well structures were studied. Micro-luminescence experiments allowed us to conclude that the sharp emission lines originate from lateral GaAlAs islands of a few μm in diameter, formed in the structure. They serve as efficient type-I recombination centers for indirect excitons and/or carriers diffusing in the GaAs / AlAs QW structure. Magneto-luminescence spectra from single islands resemble those observed for natural quantum dots formed in narrow GaAs quantum wells. The observed emission is assigned to the recombination of neutral excitons as well as excitonic molecules.

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