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We observe plasma flows in cool loops using the Slit-Jaw Imager (SJI) onboard the Interface Region Imaging Spectrometer (IRIS). Huang et al. (2015) observed unusually broadened Si IV 1403 angstrom line profiles at the footpoints of such…

Solar and Stellar Astrophysics · Physics 2020-05-27 A. K. Srivastava , Yamini K. Rao , P. Konkol , K. Murawski , M. Mathioudakis , Sanjiv K. Tiwari , E. Scullion , J. G. Doyle , B. N. Dwivedi

The CHIANTI atomic database contains atomic energy levels, wavelengths, radiative transition probabilities and electron excitation data for a large number of ions of astrophysical interest. Version 4 has been released, and proton excitation…

Astrophysics · Physics 2009-11-07 P. R. Young , G. Del Zanna , E. Landi , K. P. Dere , H. E. Mason , M. Landini

We present observations of the occulted active region AR12222 during the third {\em NuSTAR} solar campaign on 2014 December 11, with concurrent {\em SDO/}AIA and {\em FOXSI-2} sounding rocket observations. The active region produced a…

Most neighboring stars are still detected as point sources and are beyond the angular resolution reach of current observatories. Methods to improve our understanding of stars at high angular resolution are investigated. Air Cherenkov…

Instrumentation and Methods for Astrophysics · Physics 2012-09-07 Paul D. Nunez

The CHIANTI atomic database provides sets of assessed data used for simulating spectral observations of astrophysical plasmas. This article describes updates that will be released as version~10.1 of the database. A key component of CHIANTI…

Atomic Physics · Physics 2023-08-23 Kenneth Dere , Giulio Del Zanna , Peter Young , Enrico Landi

SDO/AIA images the full solar disk in several EUV bands that are each sensitive to coronal plasma emissions of one or more specific temperatures. We observe that when isolated active regions (ARs) are on the disk, full-disk images in some…

Solar and Stellar Astrophysics · Physics 2021-03-10 Talwinder Singh , Alphonse C. Sterling , Ronald L. Moore

The X-Ray Telescope (XRT) on the Japanese/USA/UK {\it Hinode (Solar-B)} spacecraft has detected emission from a quiescent active region core that is consistent with nanoflare heating. The fluxes from 10 broadband X-ray filters and filter…

Solar and Stellar Astrophysics · Physics 2009-11-13 J. T. Schmelz , S. H. Saar , E. E. DeLuca , L. Golub , V. L. Kashyap , M. A. Weber , J. A. Klimchuk

We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO). EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission…

Solar and Stellar Astrophysics · Physics 2015-06-17 Harry P. Warren

We compare the ability of 11 Differential Emission Measure (DEM) forward-fitting and inversion methods to constrain the properties of active regions and solar flares by simulating synthetic data using the instrumental response functions of…

Solar and Stellar Astrophysics · Physics 2016-04-13 M. J. Aschwanden , P. Boerner , A. Caspi , J. M. McTiernan , D. Ryan , H. P. Warren

In a first of a series of studies of the H-alpha + [NII] emission from nearby spiral galaxies, we present measurements of H-alpha + [NII] emission from HII regions in M81. Our method uses large-field-CCD images and long-slit spectra, and is…

Astrophysics · Physics 2009-11-07 W. P. Lin , X. Zhou , D. Burstein , R. A. Windhorst , J. S. Chen

The Phase-Induced Amplitude Apodization (PIAA) coronagraph is a high performance coronagraph concept able to work at small angular separation with little loss in throughput. We present results obtained with a laboratory PIAA system…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Olivier Guyon , Eugene Pluzhnik , Frantz Martinache , Julien Totems , Shinichiro Tanaka , Taro Matsuo , Celia Blain , Ruslan Belikov

Aims: Temperature uncertainties plague our understanding of abundance variations within the ISM. Using the PHANGS-MUSE large program, we develop and apply a new technique to model the strong emission lines arising from HII regions in 19…

A key goal of the Solar Orbiter mission is to connect elemental abundance measurements of the solar wind enveloping the spacecraft with EUV spectroscopic observations of their solar sources, but this is not an easy exercise. Observations…

We present a study of FeII emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ a NIR FeII…

Astrophysics of Galaxies · Physics 2016-02-17 A. O. M. Marinello , A. Rodriguez-Ardila , A. Garcia-Rissmann , T. A. A. Sigut , A. K. Pradhan

We report the first statistical analyses of [CII] and dust continuum observations in six strong OI absorber fields at the end of the reionization epoch obtained by the Atacama Large Millimeter/Submillimeter Array (ALMA). Combined with one…

We analyze the Chandra X-ray spectrum obtained with the HETGS grating spectrometer of IRAS 13349+2438, which has one of the richest absorption spectra of a quasar outflow. Absorption from almost all charge states of Fe is detected. This…

Astrophysics · Physics 2011-02-11 Tomer Holczer , Ehud Behar , Shai Kaspi

We present long-slit observations in the optical and near infrared of eight HII regions in the spiral galaxy NGC 4258. Six of the observed regions are located in the SE inner spiral arms and the other two are isolated in the northern outer…

Imaging atmospheric Cherenkov telescopes (IACTs) detect gamma rays by measuring the Cherenkov light emitted by secondary particles in the air shower when the gamma rays hit the atmosphere. At low energies, the limited amount of Cherenkov…

From Doppler velocity maps of active regions constructed from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft we observe large areas of outflow (20-50 km/s) that can persist for at least a…

Astrophysics · Physics 2009-11-13 G. A. Doschek , H. P. Warren , J. T. Mariska , K. Muglach , J. L. Culhane , H. Hara , T Watanabe

In this brief review, I give a summary of the observations of Anomalous Microwave Emission (AME) from HII regions. AME has been detected in, or in the vicinity of, HII regions. Given the difficulties in measuring accurate SEDs over a wide…

Astrophysics of Galaxies · Physics 2015-06-15 Clive Dickinson