Optical long-slit spectroscopy in the cluster Abell S0805

2019 ◽  
Vol 488 (3) ◽  
pp. 3685-3715
Author(s):  
P C da Rocha-Poppe ◽  
V A Fernandes-Martin ◽  
M Faúndez-Abans ◽  
M de Oliveira-Abans ◽  
G A Silva ◽  
...  
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Spectral Synthesis ◽  
Emission Lines ◽  
Cluster Galaxy ◽  
Nuclear Activity ◽  
Star Forming ◽  
Line Region ◽  
Nitrogen Emission ◽  
First Time

ABSTRACT This contribution aims to study the nature (kinematic, nuclear activity, and stellar population) of a sample of 10 galaxies in the poor cluster Abell S0805. As no detailed optical spectroscopy for some members has been published yet, the selected sample makes this study ideal for investigating the properties of the following objects: ESO 104- G(002, 006, 007, 008, 009, 010, 013), Fairall 0187, and PGC (062384, 062391). Our main results were obtained after subtraction of the underlying stellar population with the spectral synthesis code starlight. The residual spectra reveal seven galaxies with only absorption lines [ESO 104- G(002, 007, 008, 009), Fairall 0187 and PGC (062384, 062391)], and three galaxies with emission lines [ESO 104- G(006, 010, 013)]. According to the boundaries in the diagnostic diagrams, the intensities of H α and the low-ionization lines ([N ii] λ6584 Å and [S ii] λλ6716,6731 Å) suggest the following results: (i) the brightest cluster galaxy (ESO 104- G006, an elliptical cD galaxy) shows low-ionization nuclear emission-line region (LINER)-like excitation, quite common in ‘cool core clusters’; (ii) the ESO 104- G010 (‘X-Galaxy’ or ‘Crystal Frog’) shows an excess of the nitrogen emission-line [N ii] λ6584 Å not yet reported. We also suggest this object as a LINER; (iii) the spiral ESO 104- G013 is a star-forming galaxy with typical emission lines. No obvious signs of interaction were observed in this study. The heliocentric velocities agree within 1σ with the most recent values. The stellar population, rotation curves, and velocity dispersions are also discussed for the first time for some objects.

scholarly journals Optical spectroscopy of type 2 LINERs

2020 ◽  
Vol 635 ◽  
pp. A50
Author(s):  
L. Hermosa Muñoz ◽  
S. Cazzoli ◽  
I. Márquez ◽  
J. Masegosa
Keyword(s):  
Emission Line ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
True Nature ◽  
Star Forming ◽  
Broad Component ◽  
Line Region ◽  
Line Fitting

Context. Type 2 Low-ionization Nuclear Emission-line Regions (LINERs) have been optically classified with the Palomar data as not presenting a broad component in the Balmer emission lines that are associated with the broad-line region (BLR) of the active galactic nuclei (AGN). Aims. We aim to unveil the presence of different kinematic components of emission lines in the nuclear region of a sample of local (z ≤ 0.022) type 2 LINERs. We focus on the analysis of the true nature of LINERs by means of the detection (or nondetection) of a broad component that originated in the BLR of the AGN. Additionally, we search for the possible presence of nonrotational motions such as outflows in these LINERs. Methods. We applied a decomposition of the nuclear emission lines using an spectroscopic analysis of the optical spectra of nine type 2 LINERs of intermediate-resolution spectroscopic data retrieved from the Hubble Space Telescope (HST) archive. The study is completed with archival spectra from the Double Spectrograph from the Palomar Observatory. Results. The emission line fitting reveals the presence of a broad component associated with the BLR in six out of the nine galaxies for the space-based data, and for two out of the eight from the ground-based spectra. The velocity dispersion for two galaxies (NGC 4486 and NGC 4594) measured in HST/STIS data suggest the presence of outflows. Conclusions. The results indicate that the spatial resolution plays a major role in the detection of the BLR, as it appears diluted in the ground-based data (even after removing stellar contribution). This is also true for the emission line diagnostics, as the contaminant light contributes to lower emission line ratios toward the star-forming area of standard BPTs. We propose to reclassify NGC 4594 as a type 1 LINER, since a BLR component is seen in both space- and ground-based spectra. We find ambiguous results for the BLR component of NGC 4486. The modest outflow detection in our sample may indicate that they are not as frequent as seen for type 1 LINERs.

scholarly journals Quantifying correlations between galaxy emission lines and stellar continua using a PCA-based technique

2014 ◽  
Vol 10 (S306) ◽  
pp. 301-303
Author(s):  
Róbert Beck ◽  
László Dobos ◽  
István Csabai
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Active Galaxies ◽  
Emission Lines ◽  
Theoretical Modelling ◽  
Support Vector ◽  
Population Synthesis ◽  
Star Forming ◽  
Stellar Population Synthesis ◽  
Empirical Curve

AbstractWe analyse the correlations between continuum properties and emission line equivalent widths of star-forming and narrow-line active galaxies from SDSS. We show that emission line strengths can be predicted reasonably well from PCA coefficients of the stellar continuum using local multiple linear regression. Since upcoming sky surveys will make broadband observations only, theoretical modelling of spectra will be essential to estimate physical properties of galaxies. Combined with stellar population synthesis models, our technique will help generate more accurate model spectra and mock catalogues of galaxies to be used to fit data from new surveys. We also show that, by combining PCA coefficients from the pure continuum and the emission lines, a plausible distinction can be made between weak AGNs and quiescent star-forming galaxies. Our method uses a support vector machine, and allows a more refined separation of active and star-forming galaxies than the empirical curve of Kauffmann et al. (2003).

An Extended Emission Line Region around Mrk 1172

2019 ◽  
Vol 15 (S359) ◽  
pp. 438-440
Author(s):  
Augusto Lassen ◽  
Rogério Riffel ◽  
Ana L. Chies-Santos ◽  
Evelyn Johnston ◽  
Boris Haeussler ◽  
...  
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Emission Lines ◽  
Gas Content ◽  
Early Type ◽  
Strong Emission ◽  
Line Region ◽  
Hard Radiation ◽  
Star Formation Activity ◽  
Extended Emission

AbstractWe serendipitously found an intriguing Extended Emission Line Region (EELR) near the quiescent and massive early-type Mrk 1172, with a projected extension of approximately 14 × 14 kpc. Its irregular shape, high gas content, strong emission lines and proximity to an isolated possible faded quasar raise questions about the ionization of this gas and the nature of this object. Analyzing the stellar population in both objects we observe that the EELR has a dominance of young-intermediate and intermediate stellar populations (200 Myr < t < 1 Gyr) with significant star formation activity, while Mrk 1172 is dominated by old stellar population (t > 5 Gyr). BPT diagnostic diagrams indicate that the gas in the EELR is photoionized by hot massive stars rather than by a hard radiation field or by shocks. Further analysis on abundances of the gas and its kinematics shall be performed to better comprehend the nature of this object and how it is interacting with Mrk 1172.

scholarly journals Using stellar population studies to determine the progenitors of GRBs and SNe

2009 ◽  
Vol 5 (S262) ◽  
pp. 436-437
Author(s):  
Christina C. Thöne ◽  
Lise Christensen ◽  
Johan P. U. Fynbo
Keyword(s):  
Emission Line ◽  
Stellar Population ◽  
Population Studies ◽  
Population Models ◽  
Host Galaxy ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions

AbstractWe present spatially resolved emission line studies of three nearby GRB and SN hosts with longslit and/or IFU observations. We compare the environment of the GRBs/SNe with those of other star-forming regions in the host galaxy and try to get informations on the progenitor from stellar population models and metallicities.

scholarly journals Constraints on the production and escape of ionizing radiation from the emission-lines of metal-poor star-forming galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 121-122
Author(s):  
A. Plat ◽  
S. Charlot ◽  
G. Bruzual ◽  
A. Feltre ◽  
A. Vidal-Garca ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
High Redshift Galaxies ◽  
Star Forming ◽  
Radiative Shocks ◽  
Metal Poor Star

AbstractTo understand how the nature of the ionizing sources and the leakage of ionizing photons in high-redshift galaxies can be constrained from their emission-line spectra, we compare emission-line models of star-forming galaxies including leakage of ionizing radiation, active galactic nuclei (AGN) and radiative shocks, with observations of galaxies at various redshifts with properties expected to approach those of primeval galaxies.

scholarly journals Molecular hydrogen and [Fe ii] in active galactic nuclei – III. Low-ionization nuclear emission-line region and star-forming galaxies

2013 ◽  
Vol 430 (3) ◽  
pp. 2002-2017 ◽  
Author(s):  
R. Riffel ◽  
A. Rodríguez-Ardila ◽  
I. Aleman ◽  
M. S. Brotherton ◽  
M. G. Pastoriza ◽  
...  
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Molecular Hydrogen ◽  
Galactic Nuclei ◽  
Star Forming ◽  
Line Region

scholarly journals Raman Scattering and the Hidden He II Emission Region in the Bipolar Planetary Nebula M2-9

2003 ◽  
Vol 209 ◽  
pp. 399-400
Author(s):  
Hee-Won Lee
Keyword(s):  
Raman Scattering ◽  
Emission Line ◽  
Planetary Nebula ◽  
Emission Lines ◽  
Line Of Sight ◽  
Emission Region ◽  
Physical Size ◽  
Line Region ◽  
Region 10

In the spectrum of the young bipolar planetary nebula M2-9, we detected the He II Raman scattered feature at 6545 Å. However, in the same spectrum the He II emission lines at 6527 Å and 6560 Å are absent, which implies that the He II emission region is hidden from our line of sight and that the H I scattering region is pretty much extended not to be obscured entirely. We perform photoionization computations to estimate the physical size of the He II emission line region ≲ 1015 cm in the presence of hot luminous star with T ≳ 105 K and L ≲ 103L⊙.

scholarly journals Stellar velocity dispersions and emission line properties of SDSS-III/BOSS galaxies

2012 ◽  
Vol 8 (S295) ◽  
pp. 129-132
Author(s):  
D. Thomas ◽  
O. Steele ◽  
C. Maraston ◽  
J. Johansson ◽  
A. Beifiori ◽  
...  
Keyword(s):  
Emission Line ◽  
Velocity Dispersion ◽  
Target Selection ◽  
Emission Lines ◽  
Clear Correlation ◽  
Data Set ◽  
Star Forming ◽  
Public Data ◽  
Data Release ◽  
Stellar Velocity

AbstractWe perform a spectroscopic analysis of 492,450 galaxy spectra from the first two years of observations of the Sloan Digital Sky Survey-III/Baryonic Oscillation Spectroscopic Survey (BOSS) collaboration. This data set has been released in the ninth SDSS data release, the first public data release of BOSS spectra. We show that the typical signal-to-noise ratio of BOSS spectra is sufficient to measure stellar velocity dispersion and emission line fluxes for individual objects. The typical velocity dispersion of a BOSS galaxy is 240 km/s, with an accuracy of better than 30 per cent for 93 per cent of BOSS galaxies. The distribution in velocity dispersion is redshift independent between redshifts 0.15 and 0.7, which reflects the survey design targeting massive galaxies with an approximately uniform mass distribution in this redshift interval. The majority of BOSS galaxies lack detectable emission lines. We analyse the emission line properties and present diagnostic diagrams using the emission lines [OII], Hβ, [OIII], Halpha, and [NII] (detected in about 4 per cent of the galaxies). We show that the emission line properties are strongly redshift dependent and that there is a clear correlation between observed frame colours and emission line properties. Within in the low-z sample around 0.15 < z < 0.3, half of the emission-line galaxies have LINER-like emission line ratios, followed by Seyfert-AGN dominated spectra, and only a small fraction of a few per cent are purely star forming galaxies. AGN and LINER-like objects, instead, are less prevalent in the high-z sample around 0.4 < z < 0.7, where more than half of the emission line objects are star forming. This is a pure selection effect caused by the non-detection of weak Hβ emission lines in the BOSS spectra. Finally, we show that star forming, AGN and emission line free galaxies are well separated in the g - r vs r - i target selection diagram.

scholarly journals Chemical abundances in Seyfert galaxies – VII. Direct abundance determination of neon based on optical and infrared emission lines

2021 ◽  
Vol 508 (1) ◽  
pp. 371-391
Author(s):  
Mark Armah ◽  
O L Dors ◽  
C P Aydar ◽  
M V Cardaci ◽  
G F Hägele ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Seyfert Galaxies ◽  
Infrared Emission ◽  
Emission Lines ◽  
Chemical Abundances ◽  
Star Forming ◽  
Star Forming Regions ◽  
Abundance Estimates ◽  
Line Region ◽  
Semi Empirical

ABSTRACT For the first time, neon abundance has been derived in the narrow line region from a sample of Seyfert 2 nuclei. In view of this, we compiled from the literature fluxes of optical and infrared (IR) narrow emission lines for 35 Seyfert 2 nuclei in the local universe ($z \:\lesssim \:0.06$). The relative intensities of emission lines were used to derive the ionic and total neon and oxygen abundances through electron temperature estimations (Te-method). For the neon, abundance estimates were obtained by using both Te-method and IR-method. Based on photoionization model results, we found a lower electron temperature [$t_{\rm e}({\rm Ne\, \small {III}})$] for the gas phase where the Ne2 + is located in comparison with t3 for the O2 + ion. We find that the differences (D) between Ne2 +/H+ ionic abundances calculated from IR-method and Te-method (assuming t3 in the Ne2 +/H+ derivation) are similar to the derivations in star-forming regions (SFs) and they are reduced by a mean factor of ∼3 when $t_{\rm e}({\rm Ne\, \small {III}})$ is considered. We propose a semi-empirical Ionization Correction Factor (ICF) for the neon, based on [Ne ii]12.81$\rm{\mu m}$, [Ne iii]15.56$\rm{\mu m}$, and oxygen ionic abundance ratios. We find that the average Ne/H abundance for the Seyfert 2s sample is nearly 2 times higher than similar estimate for SFs. Finally, for the very high metallicity regime (i.e. [$\rm 12+log(O/H)\: \gtrsim \: 8.80$]) an increase in Ne/O with O/H is found, which likely indicates secondary stellar production for the neon.

scholarly journals Long Term UV Continuum and Line Variability in NGC 1275

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Bryan Rithesh Miranda ◽  
Vijayakumar H Doddamani ◽  
Vedavathi P
Keyword(s):  
Emission Line ◽  
Spectroscopic Data ◽  
Wavelength Region ◽  
Emission Lines ◽  
Observational Period ◽  
Flux Variability Analysis ◽  
Variability Analysis ◽  
Ngc 1275 ◽  
First Time

In this paper, we present our results for the first time on long term emission-line and continuum variability studies using the International Ultraviolet Explorer’s final archive of UV spectroscopic data obtained in the wavelength region from 1150 Å to 3200 Å for NGC 1275, a dust dominated BL Lac characterized by the Rmax and  F-variance parameter. The UV continuum flux variability analysis presented in this paper covers more number of emission-line free continuum windows in the UV region centred at  1710 Å, 1800 Å, 2625 Å, 2875 Å & 3025 Å. We have obtained a higher value of Fvar  ~ 45 % at 1710 Å and a lower value of ~ 30 % at 1800 Å for the IUE's observational period of 1978 - 1989. The Lyα, C IV, C III] and Mg II emission lines have been observed as weaker line features on fewer occasions intermittently.

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