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- Stars: low-mass (6)
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Articles 1 - 30 of 36
Full-Text Articles in Physical Sciences and Mathematics
Reflectance Spectroscopy Datasets For The Validation Of Tanager, Kristiana Lapo, Kathleen Hoza, Sammy Theuer, Melissa S. Rice
Reflectance Spectroscopy Datasets For The Validation Of Tanager, Kristiana Lapo, Kathleen Hoza, Sammy Theuer, Melissa S. Rice
Geology Faculty Publications
The Three-Axis N-sample Automated Goniometer for Evaluating Reflectance (TANAGER) is a custom goniometer designed to rapidly acquire spectra of natural rock surfaces across the full scattering hemisphere. TANAGER interfaces with a Malvern Panalytical ASD Fieldspec 4 Hi-Res reflectance spectrometer to collect data from 350-2500 nm at a range of incidence, emission and azimuth angles. To validate the accuracy and repeatability of data collected with TANAGER - and to characterize any instrument noise, artifacts or sample heating effects - we collected spectra from three categories of targets: (1) powdered calcium sulfate (anhydrite), (2) naturally weathered basalt surfaces, and (3) color calibration …
The Role Of Volatile Enrichment In The Radiogenic Heating And Thermal Evolution Of Rocky Exoplanets, Ula Jones, Asmaa Boujibar
The Role Of Volatile Enrichment In The Radiogenic Heating And Thermal Evolution Of Rocky Exoplanets, Ula Jones, Asmaa Boujibar
WWU Honors College Senior Projects
Internal heating in terrestrial planets is a fundamental physical process controlling the internal structure of a planet, mantle convection, volcanic activity, and the generation of magnetic fields. Internal heating results from various processes including radioactive decay and accretional energy, as well as additional irradiation and tidal heating in planets with short orbital periods. The largest long-term heat source for terrestrial planets is radioactive heating, especially from the decay of uranium (U), thorium (Th), and potassium (K) isotopes. K is a moderately volatile element, while U and Th are refractory elements; during planetary accretion volatiles are depleted relative to refractory elements, …
Mastcam Multispectral Database From The Curiosity Rover’S Traverse In Gale Crater, Mars (Sols 0-2302), Melissa S. Rice
Mastcam Multispectral Database From The Curiosity Rover’S Traverse In Gale Crater, Mars (Sols 0-2302), Melissa S. Rice
Geology Faculty Publications
The Mars Science Laboratory (MSL) Curiosity rover has explored fluvio-deltaic, lacustrine, and aeolian strata as it climbed over 400 m in elevation over the first 2302 sols of its traverse. Curiosity’s Mast Camera (Mastcam) instrument is a pair of multispectral imagers covering visible to near-infrared (VNIR) wavelengths (445 nm - 1013 nm). Mastcam spectra can broadly distinguish between iron phases and oxidation states, and in combination with chemical data from other instruments, Mastcam spectra can help constrain mineralogy, depositional origin, and diagenesis. This dataset includes representative Mastcam spectra from >600 multispectral observations acquired across Curiosity’s traverse through Vera Rubin ridge …
Physical Properties Of Brackett Emitters In The Apogee Dr17 Catalog, Elliott Khilfeh, Hunter Campbell, Kevin R. Covey, Marina Kounkel, Richard Ballentyne
Physical Properties Of Brackett Emitters In The Apogee Dr17 Catalog, Elliott Khilfeh, Hunter Campbell, Kevin R. Covey, Marina Kounkel, Richard Ballentyne
WWU Honors College Senior Projects
In the process of accumulating mass (accretion), young stars channel ionized gas from the protoplanetary disk to the stellar surface along magnetic field lines. Upon impacting the photosphere, the gas cools down, recombining and emitting hydrogen spectral lines. Measuring these emission lines allows us to determine the temperature and density of the gas in those accretion streams. This then enables us to test whether those parameters depend on the accretion rate. We present measurements of equivalent widths and line ratios for Brackett (Br) 11 – 20 lines for 3366 observations of 940 pre-main sequence stars observed with APOGEE as of …
A Neural Network Approach To Identifying Ysos And Exploring Solar Neighborhood Star-Forming History, Aidan Mcbride, Ryan Lingg, Marina Kounkel, Kevin Covey, Brian Hutchinson
A Neural Network Approach To Identifying Ysos And Exploring Solar Neighborhood Star-Forming History, Aidan Mcbride, Ryan Lingg, Marina Kounkel, Kevin Covey, Brian Hutchinson
WWU Honors College Senior Projects
Stellar ages can act as a marker of birth cluster membership for young stellar objects (YSOs), which allows for an improved understanding of the history of star formation in the solar neighborhood. However, the ages of YSOs have historically been difficult to predict on a large scale. Here, we develop a system of convolution neural network models to differentiate between YSOs and their more-evolved counterparts and predict YSO ages using Gaia and 2MASS photometry. The full model and resulting catalog recovers the properties of well-studied young stellar populations to a distance of five kiloparsecs, with significantly higher sensitivity within one …
Spectral Variability Of Weathered Basalts And Sandstones, Isabella Seppi
Spectral Variability Of Weathered Basalts And Sandstones, Isabella Seppi
WWU Honors College Senior Projects
Spectroscopy can be used to uncover the composition, and therefore the geological history, of rock surfaces and is a major tool for understanding the geologic history of rocks on Mars. The spectra taken from the rovers and orbital spacecraft and at Mars are taken at many different angles and these angles can affect the spectral readings taken from weathered rock surfaces. I will be researching how Mars analog rocks reflect light at different angles. Profs. Melissa Rice, Mike Kraft and Sean Mulcahy have received a grant from NASA to build a hemispheric goniometer which will measure spectra taken form weathered …
The Velocity Dispersion Function Of Very Massive Galaxy Clusters: Abell 2029 And Coma, Jubee Sohn, Margaret J. Geller, H. Jabran Zahid, Daniel G. Fabricant, Antonaldo Diaferio, Kenneth J. Rines
The Velocity Dispersion Function Of Very Massive Galaxy Clusters: Abell 2029 And Coma, Jubee Sohn, Margaret J. Geller, H. Jabran Zahid, Daniel G. Fabricant, Antonaldo Diaferio, Kenneth J. Rines
Physics & Astronomy
Based on an extensive redshift survey for galaxy clusters Abell 2029 and Coma, we measure the luminosity functions (LFs) and stellar mass functions (SMFs) for the entire cluster member galaxies. Most importantly, we measure the velocity dispersion functions (VDFs) for quiescent members. The MMT/Hectospec redshift survey for galaxies in A2029 identifies 982 spectroscopic members; for 838 members, we derive the central velocity dispersion from the spectroscopy. Coma is the only other cluster surveyed as densely. The LFs, SMFs, and VDFs for A2029 and Coma are essentially identical. The SMFs of the clusters are consistent with simulations. The A2029 and Coma …
Most Observations Of Our Nearest Neighbor: Flares On Proxima Centauri, James R. A. Davenport, David M. Kipping, Dimitar Sasselov, Jaymie M. Matthews, Chris Cameron
Most Observations Of Our Nearest Neighbor: Flares On Proxima Centauri, James R. A. Davenport, David M. Kipping, Dimitar Sasselov, Jaymie M. Matthews, Chris Cameron
Physics & Astronomy
We present a study of white-light flares from the active M5.5 dwarf Proxima Centauri using the Canadian microsatellite Microvariability and Oscillations of STars. Using 37.6 days of monitoring data from 2014 to 2015, we have detected 66 individual flare events, the largest number of white-light flares observed to date on Proxima Cen. Flare energies in our sample range from 1029 to 1031.5erg. The flare rate is lower than that of other classic flare stars of a similar spectral type, such as UV Ceti, which may indicate Proxima Cen had a higher flare rate in its youth. …
The Kepler Catalog Of Stellar Flares, James R. A. Davenport
The Kepler Catalog Of Stellar Flares, James R. A. Davenport
Physics & Astronomy
A homogeneous search for stellar flares has been performed using every available Kepler light curve. An iterative light curve de-trending approach was used to filter out both astrophysical and systematic variability to detect flares. The flare recovery completeness has also been computed throughout each light curve using artificial flare injection tests, and the tools for this work have been made publicly available. The final sample contains 851,168 candidate flare events recovered above the 68% completeness threshold, which were detected from 4041 stars, or 1.9% of the stars in the Kepler database. The average flare energy detected is ~1035 erg. …
The Time-Domain Spectroscopic Survey: Understanding The Optically Variable Sky With Sequels In Sdss-Iii, John J. Ruan, Scott F. Anderson, Paul J. Green, Eric Morganson, Michael Eracleous, Adam D. Myers, Carles Badenes, Matthew A. Bershady, William N. Brandt, Kenneth C. Chambers, James R. A. Davenport, Kyle S. Dawson, Heather Flewelling, Timothy M. Heckman, Jedidah C. Isler, Nick Kaiser, Jean-Paul Kneib, Chelsea L. Macleod, Isabelle Paris, Nicholas P. Ross, Jessie C. Runnoe, Edward F. Schlafly, Sarah J. Schmidt, Donald P. Schneider, Axel D. Schwope, Yue Shen, Keivan G. Stassum, Paula Szkody, Christoper Z. Waters, Donald G. York
The Time-Domain Spectroscopic Survey: Understanding The Optically Variable Sky With Sequels In Sdss-Iii, John J. Ruan, Scott F. Anderson, Paul J. Green, Eric Morganson, Michael Eracleous, Adam D. Myers, Carles Badenes, Matthew A. Bershady, William N. Brandt, Kenneth C. Chambers, James R. A. Davenport, Kyle S. Dawson, Heather Flewelling, Timothy M. Heckman, Jedidah C. Isler, Nick Kaiser, Jean-Paul Kneib, Chelsea L. Macleod, Isabelle Paris, Nicholas P. Ross, Jessie C. Runnoe, Edward F. Schlafly, Sarah J. Schmidt, Donald P. Schneider, Axel D. Schwope, Yue Shen, Keivan G. Stassum, Paula Szkody, Christoper Z. Waters, Donald G. York
Physics & Astronomy
The Time-Domain Spectroscopic Survey (TDSS) is an SDSS-IV eBOSS subproject primarily aimed at obtaining identification spectra of ~220,000 optically variable objects systematically selected from SDSS/Pan-STARRS1 multi-epoch imaging. We present a preview of the science enabled by TDSS, based on TDSS spectra taken over ~320 deg2 of sky as part of the SEQUELS survey in SDSS-III, which is in part a pilot survey for eBOSS in SDSS-IV. Using the 15,746 TDSS-selected single-epoch spectra of photometrically variable objects in SEQUELS, we determine the demographics of our variability-selected sample and investigate the unique spectral characteristics inherent in samples selected by variability. We …
Examining The Relationships Between Colour, Teff, And [M/H] For Apogee K And M Dwarfs, Sarah J. Schmidt, Erika L. Wagoner, Jennifer A. Johnson, James R. A. Davenport, Keivan G. Stassun, Diogo Souto, Jian Ge
Examining The Relationships Between Colour, Teff, And [M/H] For Apogee K And M Dwarfs, Sarah J. Schmidt, Erika L. Wagoner, Jennifer A. Johnson, James R. A. Davenport, Keivan G. Stassun, Diogo Souto, Jian Ge
Physics & Astronomy
We present the effective temperatures (Teff), metallicities, and colours in Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer filters, of a sample of 3834 late-K and early-M dwarfs selected from the SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectroscopic survey ASPCAP (APOGEE Stellar Parameters and Chemical Abundances Pipeline) catalogue. We confirm that ASPCAP Teff values between 3550 < Teff < 4200 K are accurate to ∼100 K compared to interferometric Teff values. In that same Teff range, ASPCAP metallicities are accurate to 0.18 dex between −1.0 <[M/H]g − r is not a good indicator of metallicity for near-solar metallicity early-M dwarfs. We confirm that J − KS colour is strongly dependent on metallicity, and find that W1 − W2 colour is a promising …
The Muscles Treasure Survey. I. Motivation And Overview, Kevin France, R. O. Parke Loyd, Allison Youngblood, Alexander Brown, P. Christian Schneider, Suzanne L. Hawley, Cynthia S. Froning, Jeffrey L. Linsky, Aki Roberge, Andrea P. Buccino, James R. A. Davenport, Juan M. Fontenla, Lisa Kaltenegger, Adam F. Kowalski, Pablo J. D. Mauas, Yamila Miguel, Seth Redfield, Sarah Rugheimer, Feng Tian, Mariela C. Vieytes, Lucianne M. Walkowicz, Kolby L. Weisenburger
The Muscles Treasure Survey. I. Motivation And Overview, Kevin France, R. O. Parke Loyd, Allison Youngblood, Alexander Brown, P. Christian Schneider, Suzanne L. Hawley, Cynthia S. Froning, Jeffrey L. Linsky, Aki Roberge, Andrea P. Buccino, James R. A. Davenport, Juan M. Fontenla, Lisa Kaltenegger, Adam F. Kowalski, Pablo J. D. Mauas, Yamila Miguel, Seth Redfield, Sarah Rugheimer, Feng Tian, Mariela C. Vieytes, Lucianne M. Walkowicz, Kolby L. Weisenburger
Physics & Astronomy
Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun–Earth system provides a good framework for understanding the atmospheric chemistry of Earth-like planets around solar-type stars, the observational and theoretical constraints on the atmospheres of rocky planets in the habitable zones (HZs) around low-mass stars (K and M dwarfs) are relatively few. The chemistry of these atmospheres is controlled by the shape and absolute flux of the stellar spectral …
Sn 2012cg: Evidence For Interaction Between A Normal Sn Ia And A Non-Degenerate Binary Companion, G. H. Marion, Peter J. Brown, Jozsef Vinkó, Jeffrey M. Silverman, David J. Sand, Peter Challis, Robert P. Kirshner, J. Craig Wheeler, Perry Berlind, Warren R. Brown, Michael L. Calkins, Yssavo Camacho, Govinda Dhungana, Ryan J. Foley, Andrew S. Friedman, Melissa L. Graham, D. Andrew Howell, Eric Y. Hsiao, Jonathan M. Irwin, Saurabh W. Jha, Robert Kehoe, Lucas M. Macri, Keiichi Maeda, Kaisey Mandel, Curtis Mccully, Viraj Pandya, Kenneth J. Rines, Steven Wilhelmy, Weikang Zheng
Sn 2012cg: Evidence For Interaction Between A Normal Sn Ia And A Non-Degenerate Binary Companion, G. H. Marion, Peter J. Brown, Jozsef Vinkó, Jeffrey M. Silverman, David J. Sand, Peter Challis, Robert P. Kirshner, J. Craig Wheeler, Perry Berlind, Warren R. Brown, Michael L. Calkins, Yssavo Camacho, Govinda Dhungana, Ryan J. Foley, Andrew S. Friedman, Melissa L. Graham, D. Andrew Howell, Eric Y. Hsiao, Jonathan M. Irwin, Saurabh W. Jha, Robert Kehoe, Lucas M. Macri, Keiichi Maeda, Kaisey Mandel, Curtis Mccully, Viraj Pandya, Kenneth J. Rines, Steven Wilhelmy, Weikang Zheng
Physics & Astronomy
We report evidence for excess blue light from the Type Ia supernova (Sn Ia) SN 2012cg at 15 and 16 days before maximum B-band brightness. The emission is consistent with predictions for the impact of the supernova on a non-degenerate binary companion. This is the first evidence for emission from a companion to a normal SN Ia. Sixteen days before maximum light, the color of SN 2012cg is 0.2 mag bluer than for other normal SN Ia. At later times, this supernova has a typical SN Ia light curve, with extinction-corrected mag and . Our data set is extensive, …
Hecs-Sz: The Hectospec Survey Of Sunyaev-Zeldovich-Selected Clusters, Kenneth J. Rines, Margaret J. Geller, Antonaldo Diaferio, Ho Seong Hwang
Hecs-Sz: The Hectospec Survey Of Sunyaev-Zeldovich-Selected Clusters, Kenneth J. Rines, Margaret J. Geller, Antonaldo Diaferio, Ho Seong Hwang
Physics & Astronomy
We estimate cluster masses and velocity dispersions for 123 clusters from optical spectroscopy to compare the Sunyaev–Zeldovich (SZ) mass proxy and dynamical masses. Our new survey, HeCS-SZ (Hectospec Cluster Survey of SZ-selected clusters), includes 7721 new or remeasured redshifts from MMT/Hectospec observations of 21 SZ-selected clusters at redshifts z = 0.05–0.20. We supplement the Hectospec data with spectra from the Sloan Digital Sky Survey (SDSS) and cluster data from the Cluster Infall Regions in SDSS project and the Hectospec Cluster Survey, our Hectospec survey of clusters selected by X-ray flux. We measure the scaling relation between velocity dispersion and SZ …
Hectomap And Horizon Run 4: Dense Structures And Voids In The Real And Simulated Universe, Ho Seong Hwang, Margaret J. Geller, Changbom Park, Daniel G. Fabricant, Michael J. Kurtz, Kenneth J. Rines, Juhan Kim, Antonaldo Diaferio, J. Jabran Zahid, Perry Berland, Michael Calkins, Susan Tokarz, Sean Moran
Hectomap And Horizon Run 4: Dense Structures And Voids In The Real And Simulated Universe, Ho Seong Hwang, Margaret J. Geller, Changbom Park, Daniel G. Fabricant, Michael J. Kurtz, Kenneth J. Rines, Juhan Kim, Antonaldo Diaferio, J. Jabran Zahid, Perry Berland, Michael Calkins, Susan Tokarz, Sean Moran
Physics & Astronomy
HectoMAP is a dense redshift survey of red galaxies covering a 53 deg2 strip of the northern sky. HectoMAP is 97% complete for galaxies with r < 20.5, (g− r) > 1.0, and (r − i) > 0.5. The survey enables tests of the physical properties of large-scale structure at intermediate redshift against cosmological models. We use the Horizon Run 4, one of the densest and largest cosmological simulations based on the standard Λ Cold Dark Matter (ΛCDM) model, to compare the physical properties of observed large-scale structures with simulated ones in a volume-limited sample covering 8 × 106 …
Hydrostatic And Caustic Mass Profiles Of Galaxy Clusters, Ben J. Maughan, Paul A. Giles, Kenneth J. Rines, Antonaldo Diaferio, Margaret J. Geller, Nina Van Der Pyl, Massimiliano Bonamente
Hydrostatic And Caustic Mass Profiles Of Galaxy Clusters, Ben J. Maughan, Paul A. Giles, Kenneth J. Rines, Antonaldo Diaferio, Margaret J. Geller, Nina Van Der Pyl, Massimiliano Bonamente
Physics & Astronomy
We compare X-ray and caustic mass profiles for a sample of 16 massive galaxy clusters. We assume hydrostatic equilibrium in interpreting the X-ray data, and use large samples of cluster members with redshifts as a basis for applying the caustic technique. The hydrostatic and caustic masses agree to better than ≈20 per cent on average across the radial range covered by both techniques (∼[0.2–1.25]R500). The mass profiles were measured independently and do not assume a common functional form. Previous studies suggest that, at R500 , the hydrostatic and caustic masses are biased low and high, respectively. …
Characterizing The Rigidly Rotating Magnetosphere Stars Hd 345439 And Hd 23478, J. P. Wisniewski, S. D. Chojnowski, James R. A. Davenport, J. Bartz, J. Pepper, D. G. Whelan, S. S. Eikenberry, J. R. Lomax, S. R. Majewski, N. D. Richardson
Characterizing The Rigidly Rotating Magnetosphere Stars Hd 345439 And Hd 23478, J. P. Wisniewski, S. D. Chojnowski, James R. A. Davenport, J. Bartz, J. Pepper, D. G. Whelan, S. S. Eikenberry, J. R. Lomax, S. R. Majewski, N. D. Richardson
Physics & Astronomy
The SDSS III APOGEE survey recently identified two new σ Ori E type candidates, HD 345439 and HD 23478, which are a rare subset of rapidly rotating massive stars whose large (kGauss) magnetic fields confine circumstellar material around these systems. Our analysis of multi-epoch photometric observations of HD 345439 from the Kilodegree Extremely Little Telescope, Wide Angle Search for Planets, and ASAS surveys reveals the presence of a ~0.7701 day period in each data set, suggesting the system is among the faster known σ Ori E analogs. We also see clear evidence that the strength of Hα, H …
The Eleventh And Twelfth Data Releases Of The Sloan Digital Sky Survey: Final Data From Sdss-Iii, Shadab Alam, Franco D. Albareti, Carlos Allende Prieto, F. Anders, James R. A. Davenport, Scott F. Anderson, Timothy Anderton, Brett H. Andrews, Eric Armengaud, Éric Aubourg, Stephen Bailey
The Eleventh And Twelfth Data Releases Of The Sloan Digital Sky Survey: Final Data From Sdss-Iii, Shadab Alam, Franco D. Albareti, Carlos Allende Prieto, F. Anders, James R. A. Davenport, Scott F. Anderson, Timothy Anderton, Brett H. Andrews, Eric Armengaud, Éric Aubourg, Stephen Bailey
Physics & Astronomy
The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All of the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 …
The Time Domain Spectroscopic Survey: Variable Object Selection And Anticipated Results, Eric Morganson, Paul J. Green, Scott F. Anderson, John J. Ruan, James R. A. Davenport, Adam D. Myers, Michael Eracleous, Brandon Kelly, Carlos Badenes, Eduardo Bañados, Michael R. Blanton
The Time Domain Spectroscopic Survey: Variable Object Selection And Anticipated Results, Eric Morganson, Paul J. Green, Scott F. Anderson, John J. Ruan, James R. A. Davenport, Adam D. Myers, Michael Eracleous, Brandon Kelly, Carlos Badenes, Eduardo Bañados, Michael R. Blanton
Physics & Astronomy
We present the selection algorithm and anticipated results for the Time Domain Spectroscopic Survey (TDSS). TDSS is an Sloan Digital Sky Survey (SDSS)-IV Extended Baryon Oscillation Spectroscopic Survey (eBOSS) subproject that will provide initial identification spectra of approximately 220,000 luminosity-variable objects (variable stars and active galactic nuclei across 7500 deg2 selected from a combination of SDSS and multi-epoch Pan-STARRS1 photometry. TDSS will be the largest spectroscopic survey to explicitly target variable objects, avoiding pre-selection on the basis of colors or detailed modeling of specific variability characteristics. Kernel Density Estimate analysis of our target population performed on SDSS Stripe 82 …
Detecting Differential Rotation And Starspot Evolution On The M Dwarf Gj 1243 With Kepler, James R. A. Davenport, Leslie Hebb, Suzanne L. Hawley
Detecting Differential Rotation And Starspot Evolution On The M Dwarf Gj 1243 With Kepler, James R. A. Davenport, Leslie Hebb, Suzanne L. Hawley
Physics & Astronomy
We present an analysis of the starspots on the active M4 dwarf GJ 1243, using 4 years of time series photometry from Kepler. A rapid P = 0.592596 ± 0.00021 days rotation period is measured due to the ~2.2% starspot-induced flux modulations in the light curve. We first use a light curve modeling approach, using a Monte Carlo Markov Chain sampler to solve for the longitudes and radii of the two spots within 5 day windows of data. Within each window of time the starspots are assumed to be unchanging. Only a weak constraint on the starspot latitudes can …
Boss Ultracool Dwarfs I: Colors And Magnetic Activity Of M And L Dwarfs, Sarah J. Schmidt, Suzanne L. Hawley, Andrew A. West, John J. Bochanski, James R. A. Davenport, Jian Ge, Doanld P. Schneider
Boss Ultracool Dwarfs I: Colors And Magnetic Activity Of M And L Dwarfs, Sarah J. Schmidt, Suzanne L. Hawley, Andrew A. West, John J. Bochanski, James R. A. Davenport, Jian Ge, Doanld P. Schneider
Physics & Astronomy
We present the colors and activity of ultracool (M7–L8) dwarfs from the Tenth Data Release of the Sloan Digital Sky Survey (SDSS). We combine previous samples of SDSS M and L dwarfs with new data obtained from the Baryon Oscillation Sky Survey (BOSS) to produce the BOSS Ultracool Dwarf (BUD) sample of 11820 M7–L8 dwarfs. By combining SDSS data with photometry from 2MASS and the Wide-field Infrared Sky Explorer (WISE) mission, we present ultracool dwarf colors from to as a function of spectral type, and extend the SDSS–2MASS–WISE color locus to include ultracool dwarfs. The , , …
Sdss J14584479+3720215: A Benchmark Jhks Blazar Light Curve From The 2mass Calibration Scans, James R. A. Davenport, John J. Ruan, Andrew C. Becker, Chelsea L. Macleod, Roc M. Cutri
Sdss J14584479+3720215: A Benchmark Jhks Blazar Light Curve From The 2mass Calibration Scans, James R. A. Davenport, John J. Ruan, Andrew C. Becker, Chelsea L. Macleod, Roc M. Cutri
Physics & Astronomy
Active galactic nuclei (AGNs) are well-known to exhibit flux variability across a wide range of wavelength regimes, but the precise origin of the variability at different wavelengths remains unclear. To investigate the relatively unexplored near-IR (NIR) variability of the most luminous AGNs, we conduct a search for variability using well sampled JHKs-band light curves from the Two Micron All Sky Survey (2MASS) calibration fields. Our sample includes 27 known quasars with an average of 924 epochs of observation over three years, as well as one spectroscopically confirmed blazar (SDSS J14584479+3720215) with 1972 epochs of data. This is the …
Kepler Flares Ii: The Temporal Morphology Of White-Light Flares On Gj 1243, James R. A. Davenport, Suzanne L. Hawley, Leslie Hebb, John P. Wisniewski, Adam F. Kowalski, Emily C. Johnson, Michael Malatesta, Jesus Paraza, Marcus Keil, Steven M. Silverberg, Tiffany C. Jansen, Matthew S. Scheffler, Jodi R. Berdis, Daniel M. Larsen, Eric J. Hilton
Kepler Flares Ii: The Temporal Morphology Of White-Light Flares On Gj 1243, James R. A. Davenport, Suzanne L. Hawley, Leslie Hebb, John P. Wisniewski, Adam F. Kowalski, Emily C. Johnson, Michael Malatesta, Jesus Paraza, Marcus Keil, Steven M. Silverberg, Tiffany C. Jansen, Matthew S. Scheffler, Jodi R. Berdis, Daniel M. Larsen, Eric J. Hilton
Physics & Astronomy
We present the largest sample of flares ever compiled for a single M dwarf, the active M4 star GJ 1243. Over 6100 individual flare events, with energies ranging from 1029 to 1033 erg, are found in 11 months of 1 minute cadence data from Kepler. This sample is unique for its completeness and dynamic range. We have developed automated tools for finding flares in short-cadence Kepler light curves, and performed extensive validation and classification of the sample by eye. From this pristine sample of flares we generate a median flare template. This template shows that two exponential …
Comparing Dense Galaxy Cluster Redshift Surveys With Weak-Lensing Maps, Ho Seong Hwang, Margaret J. Geller, Antonaldo Diaferio, Kenneth J. Rines, J. Jabran Zahid
Comparing Dense Galaxy Cluster Redshift Surveys With Weak-Lensing Maps, Ho Seong Hwang, Margaret J. Geller, Antonaldo Diaferio, Kenneth J. Rines, J. Jabran Zahid
Physics & Astronomy
We use dense redshift surveys of nine galaxy clusters at z ~ 0.2 to compare the galaxy distribution in each system with the projected matter distribution from weak lensing. By combining 2087 new MMT/Hectospec redshifts and the data in the literature, we construct spectroscopic samples within the region of weak-lensing maps of high (70%-89%) and uniform completeness. With these dense redshift surveys, we construct galaxy number density maps using several galaxy subsamples. The shape of the main cluster concentration in the weak-lensing maps is similar to the global morphology of the number density maps based on cluster members alone, mainly …
The Sdss–2mass–Wise 10 Dimensional Stellar Color Locus, James R. A. Davenport, Željko Ivezić, Andrew C. Becker, John J. Ruan, Nicholas M. Hunt-Walker, Kevin R. Covey, Alexia R. Lewis, Yusra Alsayyad, Lauren M. Anderson
The Sdss–2mass–Wise 10 Dimensional Stellar Color Locus, James R. A. Davenport, Željko Ivezić, Andrew C. Becker, John J. Ruan, Nicholas M. Hunt-Walker, Kevin R. Covey, Alexia R. Lewis, Yusra Alsayyad, Lauren M. Anderson
Physics & Astronomy
We present the fiducial main-sequence stellar locus traced by 10 photometric colours observed by Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey (2MASS), and Wide-field Infrared Survey Explorer(WISE). Median colours are determined using 1052 793 stars with r-band extinction less than 0.125. We use this locus to measure the dust extinction curve relative to the r band, which is consistent with previous measurements in the SDSS and 2MASS bands. The WISE band extinction coefficients are larger than predicted by standard extinction models. Using 13 lines of sight, we find variations in the extinction curve …
A Redshift Survey Of The Strong-Lensing Cluster Abell 383, Margaret J. Geller, Ho Seong Hwang, Antonaldo Diaferio, Michael J. Kurtz, Dan Coe, Kenneth J. Rines
A Redshift Survey Of The Strong-Lensing Cluster Abell 383, Margaret J. Geller, Ho Seong Hwang, Antonaldo Diaferio, Michael J. Kurtz, Dan Coe, Kenneth J. Rines
Physics & Astronomy
Abell 383 is a famous rich cluster (z = 0.1887) imaged extensively as a basis for intensive strong- and weak-lensing studies. Nonetheless, there are few spectroscopic observations. We enable dynamical analyses by measuring 2360 new redshifts for galaxies with r Petro ≤ 20.5 and within 50' of the Brightest Cluster Galaxy (BCG; R.A.2000 = 42014125, decl.2000 = –03529228). We apply the caustic technique to identify 275 cluster members within 7 h –1 Mpc of the hierarchical cluster center. The BCG lies within –11 ± 110 km s–1 and 21 ± 56 h –1 kpc of the …
Cold Gas In The Inner Regions Of Intermediate Redshift Clusters, P. Jablonka, F. Combes, Kenneth J. Rines, R. Finn, T. Welch
Cold Gas In The Inner Regions Of Intermediate Redshift Clusters, P. Jablonka, F. Combes, Kenneth J. Rines, R. Finn, T. Welch
Physics & Astronomy
Determining the nature and modes of star formation at galactic scales requires an understanding of the relationship between the gas content of a galaxy and its star formation rate. Remarkable progress has been made in understanding the conversion mechanisms in field galaxies, but the cold and dense gas fueling the star formation in galaxies inside clusters has been investigated much less often. We present the first CO observations of luminous infrared galaxies (LIRGs) inside the virial radii of two intermediate redshift clusters, CL1416+4446 (z = 0.397) and CL0926+1242 (z = 0.489). We detect three galaxies at high significance …
Measuring The Ultimate Halo Mass Of Galaxy Clusters: Redshifts And Mass Profiles From The Hectospec Cluster Survey (Hecs), Kenneth J. Rines
Measuring The Ultimate Halo Mass Of Galaxy Clusters: Redshifts And Mass Profiles From The Hectospec Cluster Survey (Hecs), Kenneth J. Rines
Physics & Astronomy
The infall regions of galaxy clusters represent the largest gravitationally bound structures in a LambdaCDM universe. Measuring cluster mass profiles into the infall regions provides an estimate of the ultimate mass of these halos. We use the caustic technique to measure cluster mass profiles from galaxy redshifts obtained with the Hectospec Cluster Survey (HeCS), an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec. We survey 58 clusters selected by X-ray flux at 0.1 < z < 0.3. The survey includes 22,680 unique MMT/Hectospec redshifts for individual galaxies; 10,145 of these galaxies are cluster members. For each cluster, we acquired high signal-to-noise spectra for ~200 cluster members and a comparable number of foreground/background galaxies. The cluster members trace out infall patterns around the clusters. The members define a very narrow red sequence. We demonstrate that the determination of velocity dispersion is insensitive to the inclusion of bluer members (a small fraction of the cluster population). We apply the caustic technique to define membership and estimate the mass profiles to large radii. The ultimate halo mass of clusters (the mass that remains bound in the far future of a LambdaCDM universe) is on average (1.99 ± 0.11)M 200, a new observational cosmological test in essential agreement with simulations. Summed profiles binned in M 200 and in LX demonstrate that the predicted Navarro-Frenk-White …
Measuring The Mass Distribution In Galaxy Clusters, Margaret J. Geller, Antonaldo Diaferio, Kenneth J. Rines, Ana Laura Serra
Measuring The Mass Distribution In Galaxy Clusters, Margaret J. Geller, Antonaldo Diaferio, Kenneth J. Rines, Ana Laura Serra
Physics & Astronomy
Cluster mass profiles are tests of models of structure formation. Only two current observational methods of determining the mass profile, gravitational lensing, and the caustic technique are independent of the assumption of dynamical equilibrium. Both techniques enable the determination of the extended mass profile at radii beyond the virial radius. For 19 clusters, we compare the mass profile based on the caustic technique with weak lensing measurements taken from the literature. This comparison offers a test of systematic issues in both techniques. Around the virial radius, the two methods of mass estimation agree to within ~30%, consistent with the expected …
The Very Short Period M Dwarf Binary Sdss J001641–000925, James R. A. Davenport, Andrew C. Becker, Andrew A. West, John J. Bochanski, Suzanne L. Hawley, Jon Holtzman, Heather C. Gunning, Eric J. Hilton, Ferah A. Munshi, Meagan Albright
The Very Short Period M Dwarf Binary Sdss J001641–000925, James R. A. Davenport, Andrew C. Becker, Andrew A. West, John J. Bochanski, Suzanne L. Hawley, Jon Holtzman, Heather C. Gunning, Eric J. Hilton, Ferah A. Munshi, Meagan Albright
Physics & Astronomy
We present follow-up observations and analysis of the recently discovered short period low-mass eclipsing binary, SDSS J001641–000925. With an orbital period of 0.19856 days, this system has one of the shortest known periods for an M dwarf binary system. Medium-resolution spectroscopy and multi-band photometry for the system are presented. Markov Chain Monte Carlo modeling of the light curves and radial velocities yields estimated masses for the stars of M 1 = 0.54 ± 0.07 M ☉ and M 2 = 0.34 ± 0.04 M ☉, and radii of R 1 = 0.68 ± 0.03 R ☉ and R 2 …