The ultraluminous X-ray source bubble in NGC 5585

ABSTRACT Some ultraluminous X-ray sources (ULXs) are surrounded by collisionally ionized bubbles, larger and more energetic than supernova remnants: they are evidence of the powerful outflows associated with super-Eddington X-ray sources. We illustrate the most recent addition to this class: a huge (350 pc × 220 pc in diameter) bubble around a ULX in NGC 5585. We modelled the X-ray properties of the ULX (a broadened-disc source with LX ≈ 2–4 × 1039 erg s−1) from Chandra and XMM–Newton, and identified its likely optical counterpart in Hubble Space Telescope images. We used the Large Binocular Telescope to study the optical emission from the ionized bubble. We show that the line emission spectrum is indicative of collisional ionization. We refine the method for inferring the shock velocity from the width of the optical lines. We derive an average shock velocity ≈125 km s−1, which corresponds to a dynamical age of ∼600 000 yr for the bubble, and an average mechanical power Pw ∼ 1040 erg s−1; thus, the mechanical power is a few times higher than the current photon luminosity. With Very Large Array observations, we discovered and resolved a powerful radio bubble with the same size as the optical bubble, and a 1.4-GHz luminosity ∼1035 erg s−1, at the upper end of the luminosity range for this type of source. We explain why ULX bubbles tend to become more radio luminous as they expand while radio supernova remnants tend to fade.

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Hubble Space Telescope observations of Europa in and out of eclipse

International Journal of Astrobiology ◽

10.1017/s1473550410000285 ◽

2010 ◽

Vol 9 (4) ◽

pp. 265-271 ◽

Cited By ~ 3

Author(s):

W.B. Sparks ◽

M. McGrath ◽

K. Hand ◽

H.C. Ford ◽

P. Geissler ◽

...

Keyword(s):

Hubble Space Telescope ◽

Broad Band ◽

Line Emission ◽

Optical Emission ◽

High Energy ◽

High Energy Particle ◽

Wide Field ◽

Particle Radiation ◽

Space Telescope ◽

Solar Blind

AbstractEuropa is a prime target for astrobiology and has been prioritized as the next target for a National Aeronautics and Space Administration flagship mission. It is important, therefore, that we advance our understanding of Europa, its ocean and physical environment as much as possible. Here, we describe observations of Europa obtained during its orbital eclipse by Jupiter using the Hubble Space Telescope. We obtained Advanced Camera for Surveys Solar Blind Channel far ultraviolet low-resolution spectra that show oxygen line emission both in and out of eclipse. We also used the Wide-Field and Planetary Camera-2 and searched for broad-band optical emission from fluorescence of the surface material, arising from the very high level of incident energetic particle radiation on ices and potentially organic substances. The high-energy particle radiation at the surface of Europa is extremely intense and is responsible for the production of a tenuous oxygen atmosphere and associated FUV line emission. Approximately 50% of the oxygen emission lasts at least a few hours into the eclipse. We discuss the detection limits of the optical emission, which allow us to estimate the fraction of incident energy reradiated at optical wavelengths, through electron-excited emission, Cherenkov radiation in the ice and fluorescent processes.

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Mixed-morphology supernova remnants: the case of SNR 0520–69.4 in the Large Magellanic Cloud

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3138 ◽

2020 ◽

Vol 499 (3) ◽

pp. 4213-4222

Author(s):

I Ramírez-Ballinas ◽

J Reyes-Iturbide ◽

P Ambrocio-Cruz ◽

R Gabbasov ◽

M Rosado

Keyword(s):

Supernova Remnants ◽

Plasma Temperature ◽

Optical Emission ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Physical Parameters ◽

X Ray ◽

Hot Plasma ◽

Observatory Data ◽

Fabry Perot

ABSTRACT We present observations in X-ray and optical emission of the supernova remnant (SNR) 0520–69.4 in the Large Magellanic Cloud. Using XMM–Newton observatory data, we produced images of the diffuse X-ray emission and spectra to obtain the X-ray parameters, such as luminosity and temperature, of hot plasma in the SNR. Diffuse X-ray emission with filled-centre morphology goes beyond the Hα region, suggesting that the hot gas escapes through the pores of the Hα shell. We fitted a model that has a plasma temperature of 1.1 × 107 K for an X-ray thermal luminosity of 3.3 × 1035 erg s−1. However, from Hα and [O iii] Fabry–Perot observations obtained with the Marseille Hα Survey of the Magellanic Clouds and the Milky Way at La Silla, European Southern Observatory, we are able to obtain physical parameters such as the velocity of the shock induced in the cloudlets emitting at optical wavelengths and the electron density of this gas. With the parameters described above, we test the model proposed by White & Long (1991, ApJ, 373, 543) for explaining the mixed-morphology observed.

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Investigation of soft X-ray emission from Ar clusters heated by ultrashort laser pulses

Laser and Particle Beams ◽

10.1017/s026303460220107x ◽

2002 ◽

Vol 20 (1) ◽

pp. 51-57 ◽

Cited By ~ 2

Author(s):

T. MOCEK ◽

C.M. KIM ◽

H.J. SHIN ◽

D.G. LEE ◽

Y.H. CHA ◽

...

Keyword(s):

Line Emission ◽

Laser Pulses ◽

Ultrashort Laser Pulses ◽

Spectral Lines ◽

Gas Temperature ◽

X Ray ◽

Charge States ◽

Ar Gas ◽

Collisional Ionization ◽

Collisional Heating

We report soft X-ray spectra (4–18 nm) produced by the interaction of 25–100-fs laser pulses at an intensity of up to 7 × 1016 W/cm2 with a cryogenically cooled Ar gas jet. New spectral lines from Ar8+, Ar9+, and Ar10+ charge states appeared with decreasing preexpansion gas temperature. A nonlinear increase of X-ray line emission from Ar7+, Ar8+, and Ar9+ was observed with cooling, which saturated below a certain temperature. The drastic change in the spectrum is attributed to efficient collisional heating and collisional ionization of growing, small- to medium-sized (102–103 atoms) Ar clusters from the cooled jet. When the laser pulse was extended from 25 to 100 fs we observed considerably stronger emission on lines from high charge states, such as Ar8+, Ar9+, and Ar10+, which suggests that the resonance absorption condition could be reached for the 100-fs pulse.

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Models for the Emission Line Spectra of Oxygen-rich Supernova Remnants

Australian Journal of Physics ◽

10.1071/ph870789 ◽

1987 ◽

Vol 40 (6) ◽

pp. 789 ◽

Cited By ~ 3

Author(s):

Michael A Dopita

Keyword(s):

Supernova Remnants ◽

Optical Emission ◽

Theoretical Modelling ◽

Optical Data ◽

X Ray ◽

Elemental Abundances ◽

Current State ◽

Enormous Amount ◽

Degree Of Confidence ◽

Cas A

The mechanism of excitation of the oxygen-rich class of young supernova remnants (SNRs), typified by the fast-moving knots of Cas A, is not currently understood. In this paper we review the available optical data and the current state of attempts at theoretical modelling. A new model is proposed which dramatically improves the fit of the theory with the observations for this class of SNRs. The model is of an X-ray driven R-type ionisation front precursor of a very fast shock. The peculiarities of the thermal balance in oxygen allow an enormous amount of superheating in the gas, which is first exposed to the X-ray ionising field, and the optical emission occurs in this superheated gas. The fit with observation is sufficiently good to give some degree of confidence that the mode of excitation of the plasma has at last been identified, and elemental abundances in four young oxygen-rich SNRs are derived.

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High-Resolution X-Ray Spectroscopy of Galactic Supernova Remnants

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2014.01.0200 ◽

2014 ◽

Vol 1 (1) ◽

pp. 200-204

Author(s):

Satoru Katsuda ◽

Hiroshi Tsunemi

Keyword(s):

High Resolution ◽

Supernova Remnants ◽

Line Emission ◽

Collisionless Shock ◽

Reverse Shock ◽

X Ray ◽

Upper Limit ◽

Hot Plasma ◽

Forward Shock ◽

Intensity Ratios

High-resolution X-ray spectroscopy of Galactic supernova remnants (SNRs), based on grating spectrometers onboard XMM-Newton and Chandra, has been revealing a variety of new astrophysical phenomena. Broadened oxygen lines for a northwestern compact knot in SN 1006 clearly show a high oxygen temperature of ~300 keV. The high temperature together with a lower electron temperature (kTe ~ 1 keV) can be reasonably interpreted as temperature non-equilibration between electrons and oxygen behind a collisionless shock. An ejecta knot in the Puppis A SNR shows blueshifted line emission by ~ 1500kms-1. The line widths are fairly narrow in contrast to the SN 1006's knot; an upper limit of 0.9 eV is obtained for O VIII Lyα, which translates to an oxygen temperature of kTO < 30 keV. The low temperature suggests that the knot was heated by a reverse shock whose velocity is 4 times slower than that of a forward shock. Anomalous intensity ratios in O VII Heα lines, i.e., a stronger forbidden line than a resonance line, is found in a cloud-shock interaction region in Puppis A. The line ratio can be best explained by the charge-exchange emission that should arise at interfaces between the cold/warm clouds and the hot plasma. There are several other targets for which we plan to analyze high-quality grating data prior to the operation of the soft X-ray spectrometer onboard Astro-H.

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Optical counterparts of an ultraluminous X-Ray Source X-1 in NGC 2500

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2160 ◽

2019 ◽

Vol 488 (4) ◽

pp. 5935-5940 ◽

Cited By ~ 1

Author(s):

N Aksaker ◽

A Akyuz ◽

S Avdan ◽

H Avdan

Keyword(s):

Hubble Space Telescope ◽

Optical Emission ◽

Spectral Energy ◽

Wide Field ◽

Nearby Galaxy ◽

X Rays ◽

Energy Distributions ◽

X Ray ◽

Photon Index ◽

Absolute Magnitudes

ABSTRACT We present the results of a search for optical counterparts of ultraluminous X-ray source (ULX) X-1 in the nearby galaxy NGC 2500 by using archival images taken with the Hubble Space Telescope Wide Field Camera (WFC3)/UVIS. We identified four optical sources as possible counterparts within the 2σ error radius of 0$^{\prime \prime }_{.}$3 in the images. However, only two of them were investigated as candidates for counterparts due to their point-like features and their identification in various filters. These two faint candidates have absolute magnitudes of MV ≈ −3.4 and −3.7. The spectral energy distributions of two candidates were modelled by a power-law spectrum with a photon index (α) ∼1.5, but the spectrum of one candidate shows a deviation. This may suggest that at least two components are responsible for the optical emission. The red part of the spectrum could arise from the companion star and the blue part could be interpreted as an evidence of reprocessing of the X-rays from the disc.

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2MASX J00423991 + 3017515: an offset active galactic nucleus in an interacting system

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab576 ◽

2021 ◽

Vol 503 (2) ◽

pp. 1688-1702

Author(s):

J Drew Hogg ◽

Laura Blecha ◽

Christopher S Reynolds ◽

Krista Lynne Smith ◽

Lisa M Winter

Keyword(s):

Active Galactic Nucleus ◽

Hubble Space Telescope ◽

Line Emission ◽

Imaging Study ◽

Host Galaxy ◽

Strong Wind ◽

X Rays ◽

Disc Galaxy ◽

Very Large Array ◽

Three Body

ABSTRACT We present a spectroscopic and imaging study of an abnormal active galactic nucleus (AGN), 2MASX J00423991 + 3017515. This AGN is newly identified in the hard X-rays by the Swift BAT All-Sky survey and found in an edge-on disc galaxy interacting with a nearby companion. Here, we analyse the first optical spectra obtained for this system (taken in 2011 and 2016), high-resolution imaging taken with the Hubble Space Telescope and Chandra X-ray Observatory, and 1 imaging with the Very Large Array. Two unique properties are revealed: the peaks of the broad Balmer emission lines (associated with gas orbiting very near the supermassive black hole) are blueshifted from the corresponding narrow line emission and host galaxy absorption by 1540 km s−1, and the AGN is spatially displaced from the apparent centre of its host galaxy by 3.8 kpc. We explore several scenarios to explain these features, along with other anomalies, and propose that 2MASX J00423991 + 3017515 may be an AGN with an unusually strong wind residing in a uniquely configured major merger, or that it is an AGN recoiling from either a gravitational ‘slingshot’ in a three-body interaction or from a kick due to the asymmetric emission of gravitational waves following the coalescence of two progenitor supermassive black holes.

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X-Ray Line Emission from Supernova Remnants and Models for Nonequilibrium Ionization

Supernova Remnants and their X-Ray Emission ◽

10.1007/978-94-009-7231-5_13 ◽

1983 ◽

pp. 109-111 ◽

Cited By ~ 1

Author(s):

Craig L. Sarazin ◽

Andrew J. S. Hamilton ◽

Roger A. Chevalier

Keyword(s):

Supernova Remnants ◽

Line Emission ◽

X Ray ◽

Nonequilibrium Ionization

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X-Ray Spectroscopic Measurements of Non-Equilibrium Ionization in Supernova Remnants

International Astronomical Union Colloquium ◽

10.1017/s0252921100085353 ◽

1984 ◽

Vol 86 ◽

pp. 76-79

Author(s):

T.H. Markert ◽

C.R. Canizares ◽

T. Pfafman ◽

P. Vedder ◽

P.F. Winkler ◽

...

Keyword(s):

Supernova Remnants ◽

X Rays ◽

Ionization Equilibrium ◽

X Ray ◽

Elemental Abundances ◽

Ion Collisions ◽

Ionization Structure ◽

Cool Plasma ◽

Collisional Ionization ◽

Time Required

When a cool plasma is shock-heated to X-ray temperatures, the ionization structure does not attain its final, equilibrium value immmediately, but proceeds toward it through electron-ion collisions with a timescale τ ≡ net of order 1012 cm−3 sec. For supernova remnants (SNRs), where 0.1 ≤ ne ≤ 10 cm−3 typically, the time required to achieve collisional ionization equilibrium (CIE) can be greater than the age of the remnant. Even if the SNR is quite old, that part of the remnant which is emitting most of the X-rays may have been shocked relatively recently, so that the assumption of CIE may be inappropriate (see below).The question of ionization equilibrium is of great astrophysical importance in the study of SNRs because it affects the deduced values of their masses and elemental abundances (e.g. Shull 1982). Mass determinations are affected because underionized plasma generally has a much higher emissivity in soft X-rays than equilibrium plasma. Unless this is accounted for, the deduced value of the density and therefore of the mass, will be considerably overestimated.

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