Spatially resolved indirect imaging of objects beyond the line of sight

2019 ◽  
Author(s):  
Prasanna Rangarajan ◽  
Florian Willomitzer ◽  
Oliver Cossairt ◽  
Marc P. Christensen
Keyword(s):  
Line Of Sight ◽  
Spatially Resolved

scholarly journals The VMC survey

2018 ◽  
Vol 613 ◽  
pp. L8 ◽  
Author(s):  
F. Niederhofer ◽  
M.-R. L. Cioni ◽  
S. Rubele ◽  
T. Schmidt ◽  
K. Bekki ◽  
...  
Keyword(s):  
Near Infrared ◽  
Two Dimensions ◽  
Magellanic Clouds ◽  
Line Of Sight ◽  
Main Body ◽  
Proper Motions ◽  
Velocity Pattern ◽  
Spatially Resolved ◽  
Magnitude Diagram ◽  
Over Time

We present the first spatially resolved map of stellar proper motions within the central (~3.1 × 2.4 kpc) regions of the Small Magellanic Cloud (SMC). The data used for this study encompasses four tiles from the ongoing near-infrared VISTA survey of the Magellanic Clouds system and covers a total contiguous area on the sky of ~6.81 deg2. Proper motions have been calculated independently in two dimensions from the spatial offsets in the Ks filter over time baselines between 22 and 27 months. The reflex motions of approximately 33 000 background galaxies are used to calibrate the stellar motions to an absolute scale. The resulting catalog is composed of more than 690 000 stars which have been selected based on their position in the (J − Ks, Ks) color-magnitude diagram. For the median absolute proper motion of the SMC, we find (μαcos(δ), μδ) = (1.087 ± 0.192 (sys.) ± 0.003 (stat.), −1.187 ± 0.008 (sys.) ± 0.003 (stat.)) mas yr−1, consistent with previous studies. Mapping the proper motions as a function of position within the SMC reveals a nonuniform velocity pattern indicative of a tidal feature behind the main body of the SMC and a flow of stars in the south-east moving predominantly along the line-of-sight.

THE 2008 MULTIWAVELENGTH CAMPAIGN OF THE TeV RADIO-GALAXY M 87

2009 ◽  
Vol 18 (10) ◽  
pp. 1493-1498
Author(s):  
◽  
PIERRE COLIN ◽  
MATTHIAS BEILICKE ◽  
FREDERICK DAVIES ◽  
D. E. HARRIS ◽  
...  
Keyword(s):  
High Resolution ◽  
Radio Galaxy ◽  
Time Correlation ◽  
Line Of Sight ◽  
Emission Process ◽  
X Ray ◽  
Cherenkov Telescopes ◽  
Extragalactic Object ◽  
Spatially Resolved ◽  
Radio Band

M 87 is the first and brightest radio galaxy detected in the TeV regime. It is the closest extragalactic object showing variability and the only one that does not have its jet pointing toward the line of sight. The structure of the M 87 jet is spatially resolved in X-ray, optical and radio observations. Time correlation between the TeV flux and emission at other wavelengths provides a unique opportunity to localize the VHE emission process occurring in active galaxy nuclei. For 10 years, M87 has been monitored in the TeV band by imaging air Cherenkov telescopes (IACT) as well as in X-ray, optical and radio bands. In 2008, the three main IACTs, H.E.S.S./MAGIC/VERITAS, coordinated their observations in a joint campaign. In February, high TeV activities with rapid flares have been detected. Contemporaneously, M 87 was observed with high resolution instruments in the X-ray (Chandra) and Radio band (VLBA).

scholarly journals Spectroscopic detection of coronal plasma flows in loops undergoing thermal non-equilibrium cycles

2020 ◽  
Vol 634 ◽  
pp. A54 ◽  
Author(s):  
Gabriel Pelouze ◽  
Frédéric Auchère ◽  
Karine Bocchialini ◽  
Clara Froment ◽  
Susanna Parenti ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Line Of Sight ◽  
Doppler Velocity ◽  
Temperature Plasma ◽  
Imaging Spectrometer ◽  
Periodic Flows ◽  
Evaporation And Condensation ◽  
Spatially Resolved ◽  
Euv Imaging ◽  
Non Equilibrium

Context. Long-period intensity pulsations were recently detected in the EUV emission of coronal loops and attributed to cycles of plasma evaporation and condensation driven by thermal non-equilibrium (TNE). Numerical simulations that reproduce this phenomenon also predict the formation of periodic flows of plasma at coronal temperatures along some of the pulsating loops. Aims. We aim to detect these predicted flows of coronal-temperature plasma in pulsating loops. Methods. We used time series of spatially resolved spectra from the EUV imaging spectrometer (EIS) onboard Hinode and tracked the evolution of the Doppler velocity in loops in which intensity pulsations have previously been detected in images of SDO/AIA. Results. We measured signatures of flows that are compatible with the simulations but only for a fraction of the observed events. We demonstrate that this low detection rate can be explained by line of sight ambiguities combined with instrumental limitations, such as low signal-to-noise ratio or insufficient cadence.

IR Structured Emission-Based Speciation, Thermometry, and Tomography of CO and H2O in High-Pressure Combustors

2006 ◽  
Author(s):  
Neil Goldstein ◽  
Brian Gregor ◽  
Jamine Lee ◽  
Stephen K. Kramer ◽  
Stuart Kozola ◽  
...  
Keyword(s):  
High Pressure ◽  
Transport Model ◽  
Radiation Transport ◽  
Chemical Species ◽  
General Purpose ◽  
Line Of Sight ◽  
Spectral Structure ◽  
Spatially Resolved ◽  
Combustion Region ◽  
Radiation Transport Model

Passive optical probes and high-resolution emission spectroscopy are used to provide a general-purpose real-time temperature and chemical species sensing capability. Probes can be inserted in the combustor, at the turbine inlet, in the augmenter, or at the engine exit with application as an engine development diagnostic tool that provides spatially resolved measurements of the key combustion parameters: temperature, CO concentration, and H2O concentration. Multiple probes are arrayed to collect the emitted infrared radiation over different views of the hot gas path. Line-of-sight averaged concentrations and temperatures are determined by spectral analysis of the emitted radiation along each line of sight (LOS). Spatial profiles may also be determined by simultaneous analysis of overlapping lines of sight. The collected infrared spectra contain optically thin and optically thick features that reflect the effects of emission and absorption within the combustion region. The known spectral structure of the component spectra can be used for the automated interpretation of the observed radiance spectra in terms of concentrations and temperatures along the line of sight, and in specific volume elements of overlapping lines of sight. In this work, we present measurements of atmospheric-pressure flames and high-pressure combustors and describe the formalism for fitting the observed spectra to a basis of simulated spectra to extract estimates of concentrations and temperatures. The spectral basis is constructed using a multilayer radiation transport model, in which each line-of-sight or measurement volume is divided into segments of uniform concentration and temperature. The observed radiance emanating from each segment is calculated as a function of the local physical variables. The collection of observed data, which contains a highly structured emission spectrum over each line of sight, is fit to the spectral basis to extract line-of-sight averaged physical properties, or in the case of spatial reconstruction, volume-averaged properties for each of the overlap regions.

scholarly journals Measuring the Distribution and Excitation of Cometary CH3OH Using ALMA

2015 ◽  
Vol 11 (A29A) ◽  
pp. 233-236 ◽  
Author(s):  
M. A. Cordiner ◽  
S. B. Charnley ◽  
M. J. Mumma ◽  
D. Bockelée-Morvan ◽  
N. Biver ◽  
...  
Keyword(s):  
Rotational Temperature ◽  
Solar Irradiation ◽  
Line Of Sight ◽  
Kinetic Temperature ◽  
Spherically Symmetric ◽  
Temperature Profiles ◽  
Spatially Resolved ◽  
Adiabatic Cooling ◽  
Excitation Processes ◽  
Spectrally Resolved

AbstractThe Atacama Large Millimeter/submillimeter Array (ALMA) was used to obtain measurements of spatially and spectrally resolved CH3OH emission from comet C/2012 K1 (PanSTARRS) on 28-29 June 2014. Detection of 12-14 emission lines of CH3OH on each day permitted the derivation of spatially-resolved rotational temperature profiles (averaged along the line of sight), for the innermost 5000 km of the coma. On each day, the CH3OH distribution was centrally peaked and approximately consistent with spherically symmetric, uniform outflow. The azimuthally-averaged CH3OH rotational temperature (Trot) as a function of sky-projected nucleocentric distance (ρ), fell by about 40 K between ρ= 0 and 2500 km on 28 June, whereas on 29 June, Trot fell by about 50 K between ρ =0 km and 1500 km. A remarkable (~50 K) rise in Trot at ρ = 1500-2500 km on 29 June was not present on 28 June. The observed variations in CH3OH rotational temperature are interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling, and heating through Solar irradiation, but collisional and radiative non-LTE excitation processes also play a role.

scholarly journals Mapping the gas thermodynamic properties of the massive cluster merger MOO J1142+1527 at z = 1.2

2020 ◽  
Vol 228 ◽  
pp. 00026
Author(s):  
F. Ruppin ◽  
R. Adam ◽  
P. Ade ◽  
P. André ◽  
A. Andrianasolo ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Angular Resolution ◽  
Morphological Properties ◽  
Line Of Sight ◽  
High Angular Resolution ◽  
Signal To Noise ◽  
X Ray ◽  
Spatially Resolved ◽  
Multi Wavelength ◽  
Massive Cluster

We present the results of the analysis of the very massive cluster MOO J1142+1527 at a redshift z = 1.2 based on high angular resolution NIKA2 Sunyaev-Zel’dovich (SZ) and Chandra X-ray data. This multi-wavelength analysis enables us to estimate the shape of the temperature profile with unprecedented precision at this redshift and to obtain a map of the gas entropy distribution averaged along the line of sight. The comparison between the cluster morphological properties observed in the NIKA2 and Chandra maps together with the analysis of the entropy map allows us to conclude that MOOJ1142+1527 is an on-going merger hosting a cool-core at the position of the X-ray peak. This work demonstrates how the addition of spatially-resolved SZ observations to low signal-to-noise X-ray data can bring valuable insights on the intracluster medium thermodynamic properties at z > 1.

scholarly journals A Cat's Eye view of the Eskimo from Saturn

2011 ◽  
Vol 7 (S283) ◽  
pp. 366-367 ◽  
Author(s):  
Maria-Teresa García-Díaz ◽  
Jose-Alberto López ◽  
Wofgang Steffen ◽  
Michael G. Richer ◽  
Hortensia Riesgo
Keyword(s):  
Three Dimensional ◽  
Line Of Sight ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Data Set ◽  
Spatially Resolved ◽  
Complex Morphology ◽  
Spectroscopic Information ◽  
Expansion Pattern ◽  
First Time

AbstractThe 3-D and kinematic structure of the Eskimo nebula, NGC 2392, has been notoriously difficult to interpret given its complex morphology, multiple kinematic components and its nearly pole-on orientation along the line of sight. Here we present the most comprehensive high resolution spectroscopic mapping of the Eskimo planetary nebula to date. The data consist of 21 spatially resolved, long-slit echelle spectra tightly spaced over the Eskimo and along its bipolar jets. This data set allowed us to construct a velocity-resolved [NII] channel map of the nebula with a resolution of 10 km/s that disentagles the differente kinematic components of the nebula and reveals clearly for the first time the kinematic expansion pattern for each of the components. The spectroscopic information is combined with a HST image to construct the first detailed three dimensional model of the Eskimo with the code SHAPE. With this model we demostrate that the Eskimo is nearly a twin to the Saturn nebula, but rotated 90° to the line sight. Furthermore, we show that the main characteristics of our model apply to the general properties of the group of elliptical planetary nebulae with ansae, once the orientation is considered.

scholarly journals X-ray analysis of SDSS J165202.60+172852.4, an obscured quasar with outflows at peak galaxy formation epoch

2021 ◽  
Vol 502 (3) ◽  
pp. 3769-3779
Author(s):  
Yuzo Ishikawa ◽  
Andy D Goulding ◽  
Nadia L Zakamska ◽  
Fred Hamann ◽  
Andrey Vayner ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Column Density ◽  
High Redshift ◽  
Accretion Disc ◽  
Emission Lines ◽  
Line Of Sight ◽  
X Ray ◽  
Spatially Resolved ◽  
Depth View ◽  
Selection Of

ABSTRACT We report on deep XMM–Newton and NuSTAR observations of the high redshift, z = 2.94, extremely red quasar (ERQ), SDSS J165202.60+172852.4, with known galactic ionized outflows detected via spatially resolved [O iii] emission lines. X-ray observations allow us to directly probe the accretion disc luminosity and the geometry and scale of the circumnuclear obscuration. We fit the spectra from the XMM–Newton/EPIC and NuSTAR detectors with a physically motivated torus model and constrain the source to exhibit a near Compton-thick column density of NH = (1.02$^{+0.76}_{-0.41}$) × 1024 cm−2, a near edge-on geometry with the line-of-sight inclination angle of θi = 85°, and a scattering fraction of fsc ∼ 3  per cent. The absorption-corrected, intrinsic 2–10 keV X-ray luminosity of L2–10= (1.4$^{+1}_{-1}$) × 1045 erg s−1 reveals a powerful quasar that is not intrinsically X-ray weak, consistent with observed trends in other ERQs. We also estimate the physical properties of the obscuration, although highly uncertain: the warm ionized scattering density of ne ∼ 7.5 × (102–103) cm−3 and the obscuration mass of $M_{\rm obsc} \sim 1.7\times (10^4\!-\!10^6)\,{\rm M}_{\odot}$. As previously suggested with shallower X-ray observations, optical and infrared selection of ERQ has proved effective in finding obscured quasars with powerful outflow signatures. Our observations provide an in-depth view into the X-ray properties of ERQs and support the conclusions of severely photon-limited studies of obscured quasar populations at high redshifts.

scholarly journals Temperature and Optical Depth Dependence of 0 VII Line Ratios with Reference to Solar Coronal Observations

1977 ◽  
Vol 43 ◽  
pp. 43-43
Author(s):  
L.W. Acton ◽  
W.A. Brown ◽  
K.T. Strong ◽  
R.C. Catura
Keyword(s):  
Optical Depth ◽  
Intensity Ratio ◽  
Resonance Scattering ◽  
Dielectronic Recombination ◽  
Line Of Sight ◽  
Low Density ◽  
Collisional Excitation ◽  
Spatially Resolved ◽  
The Difference ◽  
Thin Plasma

The intensity ratio of the sum of forbidden (3S - 1S) and intersystem (3S - 1S) lines to the resonance (1P - 1S) line of helium-like ions can serve as a useful measure of optical depth due to resonance scattering. The temperature dependence of this ratio for a low density, optically thin plasma, is examined in detail for the case of 0 VII. Collisional excitation rates with exchange contributions as well as cascades and the effect of unresolved satellite lines resulting from dielectronic recombination are included. These results are compared to spatially resolved measurements of the solar 0 VII spectrum and the difference interpreted in terms of resonance scattering into or out of the line of sight.

scholarly journals Spectroscopic Orbit of the Eclipsing Symbiotic Star CH Cyg

1988 ◽  
Vol 103 ◽  
pp. 221-222
Author(s):  
M. Mikołajewski ◽  
R. Szczerba ◽  
T. Tomov
Keyword(s):  
Emission Measure ◽  
Rotating Disk ◽  
Continuum Emission ◽  
Line Of Sight ◽  
Deep Minimum ◽  
Density Region ◽  
Radio Jets ◽  
Spatially Resolved ◽  
Before And After ◽  
Balmer Decrement

Mikołajewski et al.(1987) quoted convincing arguments that CH Cygni is eclipsing binary system:1.Photometric minima in U light were separated by 57004÷5780 days which is very close to the spectroscopic period (P=5750±250d) found by Yamashita and Maehara (1979).2.Variations of Hβ and Hγ profiles during both minima can be succesfully interpreted as an eclipse of a rotating disk or envelope from which these profiles originate (see also Fernie et al.,1986).3.The flickering activity was absent during the 1985 minimum while observed before and after the minimum.4.Only forbidden lines were unaffected by the minimum. Recently, additional arguments for the eclipsing nature of CH Cygni have been found:5.Deep minimum in the IUE integrated flux was coincided with the minimum detected in U light (Mikołajewska et al., 1987a).6.Changes of Balmer decrement and Balmer continuum emission measure suggest a presence of relatively small dense region occulted during the minimum and extended low density region coinciding with the radio jets (Mikołajewska et al., 1987b).7.Radial velocity of the jet spatially resolved by Solf (1987) in the [OIII]5007 line suggests the jet is practically perpendicular to the line of sight.

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