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We use Gemini GMOS-IFU observations of three luminous nearby Seyfert galaxies (Mrk79, Mrk348 and Mrk607) to estimate the electron temperature ($T_{\rm e}$) fluctuations in the inner 0.4-1.1 kpc region of these galaxies. Based on $T_{\rm e}$…

Astrophysics of Galaxies · Physics 2021-07-07 Rogemar A. Riffel , Oli L. Dors , Angela Krabbe , Cesar Esteban

The Rapid Oscillations in the Solar Atmosphere (ROSA) instrument reveals solar atmospheric fluctuations at high frequencies. Spectra of variations of the G-band intensity (IG) and CaII K-line intensity (IK) show correlated fluctuations…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. K. Lawrence , A. C. Cadavid , D. J. Christian , D. B. Jess , M. Mathioudakis

We present joint observations of the Sun by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). The observations were made of a solar active region on 2015 December 18 as part of the…

Solar and Stellar Astrophysics · Physics 2017-08-30 T. S. Bastian , G. Chintzoglou , B. De Pontieu , M. Shimojo , D. Schmit , J. Leenaarts , M. Loukitcheva

Observations of the Sun as a star have been key to guiding models of stellar atmospheres and additionally provide useful insights on the effects of granulation and stellar activity on radial velocity measurements. Most high resolution solar…

Instrumentation and Methods for Astrophysics · Physics 2020-03-11 Ashley D. Baker , Cullen H. Blake , Ansgar Reiners

On the Sun, the rotation periods of individual sunspots not only trace the latitude dependence of the surface rotation rate, but also provide clues as to the amount of subsurface fluid shear. In this paper we present the first measurements…

Astrophysics · Physics 2009-11-07 A. Collier Cameron , J. -F. Donati , M. Semel

Current Landsat Level 2 surface temperature products are derived using a single-channel (SC) methodology to estimate per-pixel surface temperature (ST) maps from Level~1 radiance data. A known issue with the Level 2 uncertainty, however, is…

We present a fast (<< 1 s per profile) inversion code for solar Ca II lines. The code uses an archive of spectra that are synthesized prior to the inversion under the assumption of local thermodynamic equilibrium (LTE). We show that it can…

Solar and Stellar Astrophysics · Physics 2015-06-23 C. Beck , D. Prasad Choudhary , R. Rezaei , R. E. Louis

White light flares (WLFs) are observational rarities, making them understudied events. However, optical emission is a significant contribution to flare energy budgets and the emission mechanisms responsible could have important implications…

Solar and Stellar Astrophysics · Physics 2015-06-18 Graham Stewart Kerr , Lyndsay Fletcher

We have measured the gas temperature in the IC 63 photodissociation region (PDR) using the S(1) and S(5) pure rotation lines of molecular hydrogen with SOFIA/EXES. We divide the PDR into three regions for analysis based on the illumination…

Astrophysics of Galaxies · Physics 2021-12-22 Archana Soam , B-G Andersson , Janik Karoly , Curtis DeWitt , Matthew Richter

We describe a technique for deriving effective temperatures, surface gravities, rotation velocities, and radial velocities from high resolution near-IR spectra. The technique matches the observed near-IR spectra to spectra synthesized from…

Astrophysics · Physics 2009-11-10 G. W. Doppmann , D. T. Jaffe

Accurate determination of photospheric solar abundances requires detailed modeling of the solar granulation and accounting for departures from local thermodynamical equilibrium (LTE). We argue that the forbidden C I line at 8727 A is…

Astrophysics · Physics 2009-11-07 Carlos Allende Prieto , David L. Lambert , Martin Asplund

Radio recombination lines (RRLs) can be used to determine the emission measure unambiguously along the Galactic plane. We use the deep (2100s per beam) HI Parkes Zone of Avoidance survey which includes 3 RRLs (H$166\alpha$, H$167\alpha$ and…

In the era of JWST, observations of hot Jupiter atmospheres are becoming increasingly precise. As a result, the signature of limb asymmetries due to temperature or abundance differences and the presence of aerosols can now be directly…

The latitudinal distributions of the yearly mean rotation rates measured respectively by Suzuki in 1998 and 2012 and Pulkkinen $\&$ Tuominen in 1998 are utilized to investigate internal-cycle variation of solar differential rotation. The…

Solar and Stellar Astrophysics · Physics 2015-06-16 K. J. Li , J. L. Xie , X. J. Shi

The problem on heating the atmospheres of T Tauri stars by radiation from an accretion shock has been solved. The structure and radiation spectrum of the emerging so-called hot spot have been calculated in the LTE approximation. The…

Solar and Stellar Astrophysics · Physics 2015-06-11 A. V. Dodin , S. A. Lamzin

Solar-cycle related variation of differential rotation is investigated through analyzing the rotation rates of magnetic fields, distributed along latitudes and varying with time at the time interval of August 1976 to April 2008. More…

Solar and Stellar Astrophysics · Physics 2015-06-16 K. J. Li , X. J. Shi , J. L. Xie , P. X. Gao , H. F. Liang , L. S. Zhan , W. Feng

Recent and upcoming stabilized spectrographs are pushing the frontier for Doppler spectroscopy to detect and characterize low-mass planets. Specifications for these instruments are so impressive that intrinsic stellar variability is…

Instrumentation and Methods for Astrophysics · Physics 2020-05-05 Christian Gilbertson , Eric B. Ford , Xavier Dumusque

Variations in the dust emissivity are critical for gas mass determinations derived from far-infrared observations, but also for separating dust foreground emission from the Cosmic Microwave Background (CMB). Hi-GAL observations allow us for…

Spectral observations of the solar transition region (TR) and corona show broadening of spectral lines beyond what is expected from thermal and instrumental broadening. The remaining non-thermal broadening is significant (5-30 km/s) and…

Solar and Stellar Astrophysics · Physics 2017-10-19 Bart De Pontieu , Scott McIntosh , Juan Martinez-Sykora , Hardi Peter , Tiago Pereira

We present an initial study of one of the first ALMA Band 3 observations of the Sun with the aim to characterise the diagnostic potential of brightness temperatures measured with ALMA on the Sun. The observation covers 48min at a cadence of…