scholarly journals The supernova remnant populations of the galaxies NGC 45, NGC 55, NGC 1313, NGC 7793: luminosity and excitation functions

2021 ◽  
Vol 507 (4) ◽  
pp. 6020-6036
Author(s):  
M Kopsacheili ◽  
A Zezas ◽  
I Leonidaki ◽  
P Boumis
Keyword(s):  
Luminosity Function ◽  
Supernova Remnant ◽  
Vertical Direction ◽  
Number Density ◽  
Luminosity Functions ◽  
Lower Excitation ◽  
Nearby Galaxies ◽  
Luminous Objects ◽  
Truncated Gaussian ◽  
Alpha Function

ABSTRACT We present a systematic study of the supernova remnant (SNR) populations in the nearby galaxies NGC 45, NGC 55, NGC 1313, and NGC 7793 based on deep H $\rm {\alpha }$ and [S ii] imaging. We find 42 candidate and 51 possible candidate SNRs based on the [S ii]/H $\rm {\alpha }$>0.4 criterion, 81 of which are new identifications. We derive the H $\rm {\alpha }$ and the joint [S ii]–H $\rm {\alpha }$ luminosity functions after accounting for incompleteness effects. We find that the H $\rm {\alpha }$ luminosity function of the overall sample is described with a skewed Gaussian with a mean equal to $\rm \log (L_{H\alpha }/10^{36}\, erg\, s^{-1})=0.07$ and $\rm \sigma (\log (L_{H\alpha }/10^{36}\, erg\, s^{-1}))=0.58$. The joint [S ii]–H $\rm {\alpha }$ function is parametrized by a skewed Gaussian along the log([S ii]$\rm /10^{36}\, erg\, s^{-1}) = 0.88 \times \log (L_{H\alpha }/10^{36}\, erg\, s^{-1}) - 0.06$ line and a truncated Gaussian with $\rm \mu (\log (L_{[S\, II]}/10^{36})) = 0.024$ and $\rm \sigma (\log (L_{[S\, II]}/10^{36})) = 0.14$, on its vertical direction. We also define the excitation function as the number density of SNRs as a function of their [S ii]/H $\rm {\alpha }$ ratios. This function is represented by a truncated Gaussian with a mean at −0.014. We find a sub-linear [S ii]–H $\rm {\alpha }$ relation indicating lower excitation for the more luminous objects.

scholarly journals Extending the White Dwarf Sequence: Plans and Prospects

1978 ◽  
Vol 80 ◽  
pp. 437-440
Author(s):  
James Liebert
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Luminosity Function ◽  
Selection Effects ◽  
Number Density ◽  
Low Velocity ◽  
Luminosity Functions ◽  
Current Sample ◽  
The Many

The recent discovery that the parallax star LP701-29 is a white dwarf has firmly extended the degenerate sequence below MV= +16m(Dahnet al. 1978). As the search for white dwarfs extends to cooler and fainter stars, however, it becomes particularly important to develop a plan for selecting candidates among the many thousands of red proper motion stars. We begin by assessing the completeness of the known sample within 10 parsecs in the northern two thirds of the sky. Some color-dependent selection effects must be evaluated, however, since these may preferentially inhibit the discovery of cooler stars. A correction factor for the missing low velocity white dwarfs is estimated. Then, Green's(1977) recent determination of the number density of blue degenerates is used to normalize various theoretical luminosity functions, the benchmarks against which the current sample out to 10 pc can be compared. It is concluded that the sample may be approaching completeness in the northern sky for white dwarfs with tangential velocities (vT) ≥ 40 km/sec (μ ≥ 1″.0/yr.) and Mbol< +15m. The implied luminosity function is thus consistent with that found by Sion and Liebert (1977). Below Mbol= +15mthe different theoretical functions predict substantially different numbers.

scholarly journals The planetary nebulae luminosity function and distances to the Virgo, Hydra i, and Coma Clusters

2012 ◽  
Vol 8 (S289) ◽  
pp. 287-291
Author(s):  
Magda Arnaboldi ◽  
Alessia Longobardi ◽  
Ortwin Gerhard ◽  
S. Okamura
Keyword(s):  
Planetary Nebula ◽  
Luminosity Function ◽  
Planetary Nebulae ◽  
Central Star ◽  
Virgo Cluster ◽  
Cluster Galaxies ◽  
Physical Mechanisms ◽  
Luminosity Functions ◽  
Brightest Cluster Galaxies ◽  
Nearby Galaxies

AbstractThe luminosity function of planetary nebula populations in galaxies at distances within 10–15 Mpc exhibits a cut-off at bright magnitudes and a functional form that is observed to be invariant among different galactic morphological types. Therefore, it is used as a secondary distance indicator applicable to both early- and late-type galaxies. Recent deep surveys of planetary nebula populations in brightest cluster galaxies (BCGs) seem to indicate that their luminosity functions deviate from those observed in the nearby galaxies. We discuss the evidence for such deviations in the Virgo Cluster, and indicate which physical mechanisms may alter the evolution of a planetary nebula envelope and its central star in the halo of BCGs. We then discuss preliminary results for distances to the Virgo, Hydra i, and Coma Clusters based on the observed planetary nebulae luminosity functions.

scholarly journals Luminosity Function and Spatial Distribution of Nearby Galaxies

1994 ◽  
Vol 161 ◽  
pp. 577-581
Author(s):  
K.-H. Schmidt ◽  
T. Boller
Keyword(s):  
Spatial Distribution ◽  
Environmental Effects ◽  
Luminosity Function ◽  
Low Density ◽  
Clusters Of Galaxies ◽  
Complete Sample ◽  
Nearby Galaxies ◽  
Luminous Objects

The investigation of environmental effects is a topic of high priority in current extragalactic research. In this connection, the study of neighbouring galaxies will result in characteristic properties of a low-density sample of extragalactic systems which may be used for comparison with other samples, with clusters of galaxies, for instance. The advantage of nearby galaxies is that they allow us to obtain an almost complete sample down to low-luminous objects because of their small distances.

scholarly journals Carbon stars as standard candles – II. The median J magnitude as a distance indicator

2020 ◽  
Vol 501 (1) ◽  
pp. 933-947
Author(s):  
Javiera Parada ◽  
Jeremy Heyl ◽  
Harvey Richer ◽  
Paul Ripoche ◽  
Laurie Rousseau-Nepton
Keyword(s):  
Luminosity Function ◽  
Asymptotic Giant Branch ◽  
Distance Modulus ◽  
Asymptotic Giant Branch Stars ◽  
Luminosity Functions ◽  
Best Fitting ◽  
Distance Indicator ◽  
Ngc 6822 ◽  
The Given ◽  
Giant Branch Stars

ABSTRACT We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J − Ks)0, J0) colour–magnitude diagrams, as, in this combination of filters, CS are bright and easy to identify. We fit the CS J-band luminosity functions using a Lorentzian distribution modified to allow the distribution to be asymmetric. We use the parameters of the best-fitting distribution to determine if the CS luminosity function of a given galaxy resembles that of the LMC or SMC. Based on this resemblance, we use either the LMC or SMC as the calibrator and estimate the distance to the given galaxy using the median J magnitude ($\overline{J}$) of the CS samples. We apply this new method to the two Local Group galaxies NGC 6822 and IC 1613. We find that NGC 6822 has an ‘LMC-like’ CS luminosity function, while IC 1613 is more ‘SMC-like’. Using the values for the median absolute J magnitude for the LMC and SMC found in Paper I we find a distance modulus of μ0 = 23.54 ± 0.03 (stat) for NGC 6822 and μ0 = 24.34 ± 0.05 (stat) for IC 1613.

scholarly journals Cosmological evolution of the AGN kinetic luminosity function

2006 ◽  
Vol 2 (S238) ◽  
pp. 65-70
Author(s):  
Andrea Merloni ◽  
Sebastian Heinz
Keyword(s):  
Galaxy Formation ◽  
Luminosity Function ◽  
Cosmological Evolution ◽  
Energy Output ◽  
Theoretical Assumption ◽  
X Ray ◽  
Spectrum Radio ◽  
Luminosity Functions ◽  
Jet Power ◽  
Joint Evolution

AbstractWe present a first attempt to derive the cosmological evolution of the kinetic luminosity function of AGN based on the joint evolution of the flat spectrum radio and hard X-ray selected AGN luminosity functions. An empirical correlation between jet power and radio core luminosity is found, which is consistent with the theoretical assumption that, below a certain Eddington ratio, SMBH accrete in a radiatively inefficient way, while most of the energy output is in the form of kinetic energy.We show how the redshift evolution of the kinetic power density from such a low-ṁ mode of accretion makes it a good candidate to explain the so-called “radio mode” of AGN feedback as outlined in many galaxy formation schemes.

scholarly journals A multispectral analysis of the northeastern shell of IC 443

2019 ◽  
Vol 489 (3) ◽  
pp. 3042-3058 ◽  
Author(s):  
Alexandre Alarie ◽  
Laurent Drissen
Keyword(s):  
Supernova Remnant ◽  
Optical Observations ◽  
Spectral Variation ◽  
Number Density ◽  
Line Intensities ◽  
Shock Density ◽  
Multispectral Analysis ◽  
Morphological Differences ◽  
Imaging Spectrograph ◽  
Single Set

Abstract We have carried out optical observations of the northeastern part of the supernova remnant IC 443 using the Canada–France–Hawaii Telescope imaging spectrograph SITELLE. The observations consist of three multispectral cubes covering an 11′ × 11′ area allowing the investigation of both the spatial and spectral variation of nine emission lines:  [O ii] λλ3726 + 3729,  [O iii] λλ4959, 5007,  H β,  H α,  [N ii] λλ6548, 6583, and  [S ii] λλ6716, 6731. Extinction measurement from the  H α/ H β shows significant variation across the observed region with E(B − V) = 0.8–1.1. Electron density measurements using  [S ii] lines indicate densities ranging from 100 up to 2500  cm−3. Models computed with the shock modelling code mappings are presented and compared with the observations. A combination of complete shock model and truncated ones is required in order to explain the observed spectrum. The shock velocities found in IC 443 are between 20 and 150  km s−1, with 75  km s−1 being the most prominent velocity. The pre-shock number density varies from 20 to 60  cm−3. A single set of abundances close to solar values combined with varying shock parameters (shock velocity, pre-shock density, and shock age) is sufficient to explain the great variation of line intensities observed in IC 443. Despite the relatively modest spectral resolution of the data (R ∼ 1500 at  H α), we clearly separate the red and blue velocity components of the expanding nebula, which show significant morphological differences.

scholarly journals Evolution of the AGN UV luminosity function from redshift 7.5

2019 ◽  
Vol 488 (1) ◽  
pp. 1035-1065 ◽  
Author(s):  
Girish Kulkarni ◽  
Gábor Worseck ◽  
Joseph F Hennawi
Keyword(s):  
Active Galactic Nuclei ◽  
Luminosity Function ◽  
Galactic Nuclei ◽  
Systematic Errors ◽  
Selection Function ◽  
Data Sets ◽  
Multiple Data ◽  
Luminosity Functions ◽  
Multiple Data Sets ◽  
Photoionization Rate

ABSTRACTDeterminations of the ultraviolet (UV) luminosity function of active galactic nuclei (AGN) at high redshifts are important for constraining the AGN contribution to reionization and understanding the growth of supermassive black holes. Recent inferences of the luminosity function suffer from inconsistencies arising from inhomogeneous selection and analysis of data. We address this problem by constructing a sample of more than 80 000 colour-selected AGN from redshift $z$ = 0 to 7.5 using multiple data sets homogenized to identical cosmologies, intrinsic AGN spectra, and magnitude systems. Using this sample, we derive the AGN UV luminosity function from redshift $z$ = 0 to 7.5. The luminosity function has a double power-law form at all redshifts. The break magnitude M* shows a steep brightening from M* ∼ −24 at $z$ = 0.7 to M* ∼ −29 at $z$ = 6. The faint-end slope β significantly steepens from −1.9 at $z$ < 2.2 to −2.4 at $z$ ≃ 6. In spite of this steepening, the contribution of AGN to the hydrogen photoionization rate at $z$ ∼ 6 is subdominant (<3 per cent), although it can be non-negligible (∼10 per cent) if these luminosity functions hold down to M1450 = −18. Under reasonable assumptions, AGN can reionize He ii by redshift $z$ = 2.9. At low redshifts ($z$ < 0.5), AGN can produce about half of the hydrogen photoionization rate inferred from the statistics of H i absorption lines in the intergalactic medium. Our analysis also reveals important systematic errors in the data, which need to be addressed and incorporated in the AGN selection function in future in order to improve our results. We make various fitting functions, codes, and data publicly available.

scholarly journals The WIRCam Ultra Deep Survey (WUDS)

2018 ◽  
Vol 620 ◽  
pp. A51 ◽  
Author(s):  
R. Pelló ◽  
P. Hudelot ◽  
N. Laporte ◽  
Y. Mellier ◽  
H. J. McCracken ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Formation Rate ◽  
Forthcoming Paper ◽  
Spectroscopic Studies ◽  
Photometric Redshifts ◽  
Near Ir ◽  
Luminosity Functions ◽  
The Galaxy ◽  
Deep Survey ◽  
Galaxy Population

The aim of this paper is to introduce the WIRCam Ultra Deep Survey (WUDS), a near-IR photometric survey carried out at the CFH Telescope in the field of the CFHTLS-D3 field (Groth Strip). WUDS includes four near-IR bands (Y, J, H and Ks) over a field of view of ∼400 arcmin2. The typical depth of WUDS data reaches between ∼26.8 in Y and J, and ∼26 in H and Ks (AB, 3σ in 1.3″ aperture), whereas the corresponding depth of the CFHTLS-D3 images in this region ranges between 28.6 and 29 in ugr, 28.2 in i and 27.1 in z (same S/N and aperture). The area and depth of this survey were specifically tailored to set strong constraints on the cosmic star formation rate and the luminosity function brighter or around L⋆ in the z ∼ 6 − 10 redshift domain, although these data are also useful for a variety of extragalactic projects. This first paper is intended to present the properties of the public WUDS survey in details: catalog building, completeness and depth, number counts, photometric redshifts, and global properties of the galaxy population. We have also concentrated on the selection and characterization of galaxy samples at z ∼ [4.5 − 7] in this field. For these purposes, we include an adjacent shallower area of ∼1260 arcmin2 in this region, extracted from the WIRCam Deep Survey (WIRDS), and observed in J, H and Ks bands. UV luminosity functions were derived at z ∼ 5 and z ∼ 6 taking advantage from the fact that WUDS covers a particularly interesting regime at intermediate luminosities, which allows a combined determination of M⋆ and Φ⋆ with increased accuracy. Our results on the luminosity function are consistent with a small evolution of both M⋆ and Φ⋆ between z = 5 and z = 6, irrespective of the method used to derive them, either photometric redshifts applied to blindly-selected dropout samples or the classical Lyman Break Galaxy color-preselected samples. Our results lend support to higher Φ⋆ determinations at z = 6 than usually reported. The selection and combined analysis of different galaxy samples at z ≥ 7 will be presented in a forthcoming paper, as well as the evolution of the UV luminosity function between z ∼ 4.5 and 9. WUDS is intended to provide a robust database in the near-IR for the selection of targets for detailed spectroscopic studies, in particular for the EMIR/GTC GOYA Survey.

scholarly journals GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION

2013 ◽  
Vol 53 (A) ◽  
pp. 612-616
Author(s):  
Manami Sasaki
Keyword(s):  
Particle Acceleration ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Strong Shock ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
X Rays ◽  
Basic Physics ◽  
Nearby Galaxies ◽  
Radiation Processes

Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed.

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