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Response of the Photospheric Magnetic Field to the X2.2 Flare on 2011 February 15
Liu, Yang; Liu, Chang; Wang, Haimin +3 more
It is well known that the long-term evolution of the photospheric magnetic field plays an important role in building up free energy to power solar eruptions. Observations, despite being controversial, have also revealed a rapid and permanent variation of the photospheric magnetic field in response to the coronal magnetic field restructuring during…
Deep Near-infrared Spectroscopy of Passively Evolving Galaxies at z >~ 1.4
Cimatti, A.; Daddi, E.; Sanders, D. B. +21 more
We present the results of new near-IR spectroscopic observations of passive galaxies at z >~ 1.4 in a concentration of BzK-selected galaxies in the COSMOS field. The observations have been conducted with Subaru/MOIRCS, and have resulted in absorption lines and/or continuum detection for 18 out of 34 objects. This allows us to measure spectrosco…
How Do Star-forming Galaxies at z > 3 Assemble Their Masses?
Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro +8 more
We investigate how star-forming galaxies typically assemble their masses at high redshift. Taking advantage of the deep multi-wavelength coverage of the GOODS data set, we select two of the largest samples of high-redshift star-forming galaxies based on their UV colors and measure stellar mass of individual galaxies. We use template-fitting photom…
CLASH: Precise New Constraints on the Mass Profile of the Galaxy Cluster A2261
Donahue, Megan; Broadhurst, Tom; Maoz, Dan +43 more
We precisely constrain the inner mass profile of A2261 (z = 0.225) for the first time and determine that this cluster is not "overconcentrated" as found previously, implying a formation time in agreement with ΛCDM expectations. These results are based on multiple strong-lensing analyses of new 16-band Hubble Space Telescope imaging obtained as par…
Solar Magnetic Field Reversals and the Role of Dynamo Families
Hoeksema, J. T.; Brun, A. S.; DeRosa, M. L.
The variable magnetic field of the solar photosphere exhibits periodic reversals as a result of dynamo activity occurring within the solar interior. We decompose the surface field as observed by both the Wilcox Solar Observatory and the Michelson Doppler Imager into its harmonic constituents, and present the time evolution of the mode coefficients…
A New Low Magnetic Field Magnetar: The 2011 Outburst of Swift J1822.3-1606
Campana, S.; Tiengo, A.; Götz, D. +20 more
We report on the long-term X-ray monitoring with Swift, RXTE, Suzaku, Chandra, and XMM-Newton of the outburst of the newly discovered magnetar Swift J1822.3-1606 (SGR 1822-1606), from the first observations soon after the detection of the short X-ray bursts which led to its discovery, through the first stages of its outburst decay (covering the ti…
Discovery of a Dissociative Galaxy Cluster Merger with Large Physical Separation
Bradač, Maruša; Hughes, John P.; Dawson, William A. +10 more
We present DLSCL J0916.2+2951 (z = 0.53), a newly discovered major cluster merger in which the collisional cluster gas has become dissociated from the collisionless galaxies and dark matter (DM). We identified the cluster using optical and weak-lensing observations as part of the Deep Lens Survey. Our follow-up observations with Keck, Subaru, Hubb…
The Bright End of the Ultraviolet Luminosity Function at z ~ 8: New Constraints from CANDELS Data in GOODS-South
Trenti, M.; Oesch, P. A.; Carollo, C. M. +7 more
We present new z ~ 8 galaxy candidates from a search over ~95 arcmin2 of WFC3/IR data, tripling the previous search area for bright z ~ 8 galaxies. Our analysis uses newly acquired WFC3/IR imaging data from the CANDELS Multi-Cycle Treasury program over the GOODS-South field. These new data are combined with existing deep optical Advance…
Vertical Atmospheric Structure in a Variable Brown Dwarf: Pressure-dependent Phase Shifts in Simultaneous Hubble Space Telescope-Spitzer Light Curves
Burrows, Adam; Showman, Adam P.; Apai, Dániel +6 more
Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASS J22282889-431026 over the wavelength ranges 1.1-1.7 µm and broadband 4.5 µm. Spectroscopic observations were taken with Wide Field …
Keck Spectroscopy of Faint 3 < z < 7 Lyman Break Galaxies. III. The Mean Ultraviolet Spectrum at z ~= 4
Stark, Daniel P.; Ellis, Richard S.; Jones, Tucker
We present and discuss the mean rest-frame ultraviolet spectrum for a sample of 81 Lyman break galaxies (LBGs) selected to be B-band dropouts at z ~= 4. The sample is mostly drawn from our ongoing Keck/DEIMOS survey in the GOODS fields and augmented with archival Very Large Telescope data. In general, we find similar spectroscopic trends to those …