Suvrath Mahadevan
ASSOCIATE PROFESSOR, Department of Astronomy and Astrophysics | Pennsylvania State University
University Park, PA, UNITED STATES
Suvrath Mahadevan is an expert in physics and astronomy.
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Industry Expertise (2)
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Areas of Expertise (4)
Data Analysis
Science
Physics and Astronomy
Statistics
Education (1)
University of Florida: Ph.D. 2006
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Languages (2)
- Hindi
- Tamil
Media Appearances (1)
New telescope attachment allows ground-based observations of new worlds
Eureka Alert online
2017-10-06
"Beam-shaping diffusers are made using a precise nanofabrication process," said Suvrath Mahadevan, associate professor of astronomy and astrophysics at Penn State and an author of the paper, "where a carefully designed surface pattern is precisely written on a plastic polymer on a glass surface or directly etched on the glass itself. The pattern consists of precise micro-scale structures, engineered to mold the varying light input from stars into a predefined broad and stable output shape spread over many pixels on the telescope camera." (...)
Articles (5)
Chemical Abundances of M-Dwarfs from the Apogee Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186
The Astrophysical Journal
Diogo Souto, Katia Cunha, DA Garcia-Hernandez, Olga Zamora, C Allende Prieto, VV Smith, Suvrath Mahadevan, Cullen Blake, JA Johnson, H Jönsson, Marc Pinsonneault, Jon Holtzman, SR Majewski, Matthew Shetrone, Johanna Teske, David Nidever, Ricardo Schiavon, Jennifer Sobeck, AE García Pérez, Y Gómez Maqueo Chew, Keivan Stassun
2017 We report the first detailed chemical abundance analysis of the exoplanet-hosting M-dwarf stars Kepler-138 and Kepler-186 from the analysis of high-resolution (R ~ 22,500) H-band spectra from the SDSS-IV–APOGEE survey. Chemical abundances of 13 elements—C, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, and Fe—are extracted from the APOGEE spectra of these early M-dwarfs via spectrum syntheses computed with an improved line list that takes into account H2O and FeH lines. This paper demonstrates that APOGEE spectra can be analyzed to determine detailed chemical compositions of M-dwarfs.
Frequency stability characterization of a broadband fiber Fabry-Perot interferometer
arXiv preprint arXiv:1703.00001
Jeff Jennings, Samuel Halverson, Ryan Terrien, Suvrath Mahadevan, Gabriel Ycas, Scott A Diddams
2017 An optical etalon illuminated by a white light source provides a broadband comb-like spectrum that can be employed as a calibration source for astronomical spectrographs in radial velocity (RV) surveys for extrasolar planets. For this application the frequency stability of the etalon is critical, as its transmission spectrum is susceptible to frequency fluctuations due to changes in cavity temperature, optical power and input polarization. In this paper we present a laser frequency comb measurement technique to characterize the frequency stability of a custom-designed fiber Fabry-Perot interferometer (FFP).
Proxima Centauri as a Benchmark for Stellar Activity Indicators in the Near-infrared
The Astrophysical Journal
Paul Robertson, Chad Bender, Suvrath Mahadevan, Arpita Roy, Lawrence W Ramsey
2016 A new generation of dedicated Doppler spectrographs will attempt to detect low-mass exoplanets around mid- to late M stars at near-infrared (NIR) wavelengths, where those stars are brightest and have the most Doppler information content. A central requirement for the success of these instruments is to properly measure the component of radial velocity (RV) variability contributed by stellar magnetic activity and to account for it in exoplanet models of RV data. The wavelength coverage for many of these new instruments will not include the Ca ii H&K or Hα lines, the most frequently used absorption-line tracers of magnetic activity. Thus, it is necessary to define and characterize NIR activity indicators for mid- to late M stars in order to provide simultaneous activity metrics for NIR RV data. We have used the high-cadence UVES observations of the M5.5 dwarf Proxima Centauri from Fuhrmeister et al. to compare the activity sensitivity of eight NIR atomic lines to that of Hα.
A Versatile Technique to Enable Sub-milli-Kelvin Instrument Stability for Precise Radial Velocity Measurements: Tests with the Habitable-zone Planet Finder
The Astrophysical Journal
Gudmundur Stefansson, Frederick Hearty, Paul Robertson, Suvrath Mahadevan, Tyler Anderson, Eric Levi, Chad Bender, Matthew Nelson, Andrew Monson, Basil Blank, Samuel Halverson, Chuck Henderson, Lawrence Ramsey, Arpita Roy, Christian Schwab, Ryan Terrien
2016 Insufficient instrument thermomechanical stability is one of the many roadblocks for achieving 10 cm s−1 Doppler radial velocity precision, the precision needed to detect Earth-twins orbiting solar-type stars. Highly temperature and pressure stabilized spectrographs allow us to better calibrate out instrumental drifts, thereby helping in distinguishing instrumental noise from astrophysical stellar signals. We present the design and performance of the Environmental Control System (ECS) for the Habitable-zone Planet Finder (HPF), a high-resolution (R = 50,000) fiber-fed near-infrared (NIR) spectrograph for the $10\,{\rm{m}}$ Hobby–Eberly Telescope at McDonald Observatory.
The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
Astronomical Journal
Steven R Majewski, Ricardo Schiavon, Peter M Frinchaboy, Carlos Allende Prieto, Robert Barkhouser, Dmitry Bizyaev, Basil Blank, Sophia Brunner, Adam Burton, Ricardo Carrera, S Drew Chojnowski, Kátia Cunha, Courtney Epstein, Greg Fitzgerald, Ana E García García, Fred R Hearty, Chuck Henderson, Jo Holtzman, Jo Johnson, Charles R Lam, James E Lawler, Paul Maseman, Szabolcs Mészáros, Matthew Nelson, Duy Coung Nguyen, David L Nidever, Marc Pinsonneault, Matthew Shetrone, Stephen Smee, Verne V Smith, Todd Stolberg, Michael F Skrutskie, Eric Walker, Jo Wilson, Gail Zasowski, Friedrich Anders, Sarbani Basu, Stephane Beland, Michael R Blanton, Jo Bovy, Joel R Brownstein, Joleen Carlberg, William Chaplin, Cristina Chiappini, Daniel J Eisenstein, Yvonne Elsworth, Diane Feuillet, Scott W Fleming, Jessica Galbraith-Frew, Rafael A Garcia, D Aníbal García-Hernández, Bruce A Gillespie, Léo Girardi, James E Gunn, Sten Hasselquist, Michael R Hayden, Saskia Hekker, Inese Ivans, Karen Kinemuchi, Mark Klaene, Suvrath Mahadevan, Savita Mathur, Benoit Mosser, Demitri Muna, Jeffrey A Munn, Robert C Nichol, Robert W O’connell, John K Parejko, AC Robin, Helio Rocha-Pinto, Matthias Schultheis, Aldo M Serenelli, Neville Shane, Victor Silva Aguirre, Jennifer S Sobeck, Benjamin Thompson, Nicholas W Troup, David H Weinberg, Olga Zamora
2017 The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three year observing campaign on the Sloan 2.5-m Telescope, APOGEE has collected a half million high resolution (R ∼ 22, 500), high S/N (>100), infrared (1.51-1.70 µm) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design — hardware, field placement, target selection, operations — and gives an overview of these aspects as well as the data reduction, analysis and products. A
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