Search Publications
Beyond Ellipse(s): Accurately Modelling the Isophotal Structure of Galaxies with ISOFIT and CMODEL
Ciambur, B. C.
This work introduces a new fitting formalism for isophotes that enables more accurate modeling of galaxies with non-elliptical shapes, such as disk galaxies viewed edge-on or galaxies with X-shaped/peanut bulges. Within this scheme, the angular parameter that defines quasi-elliptical isophotes is transformed from the commonly used, but inappropria…
The Brightest Young Star Clusters in NGC 5253.
Schaerer, D.; Östlin, G.; Herrero, A. +43 more
The nearby dwarf starburst galaxy NGC 5253 hosts a number of young, massive star clusters, the two youngest of which are centrally concentrated and surrounded by thermal radio emission (the “radio nebula”). To investigate the role of these clusters in the starburst energetics, we combine new and archival Hubble Space Telescope images of NGC 5253 w…
Strong C+ Emission in Galaxies at z ~ 1-2: Evidence for Cold Flow Accretion Powered Star Formation in the Early Universe
Spoon, Henrik; Verma, Aprajita; Nikola, Thomas +5 more
We have recently detected the [C II] 157.7 µm line in eight star-forming galaxies at redshifts 1 to 2 using the redshift (z) Early Universe Spectrometer (ZEUS). Our sample targets star formation dominant sources detected in PAH emission. This represents a significant addition to [C II] observations during the epoch of peak star formation. We…
The Formation of IRIS Diagnostics. V. A Quintessential Model Atom of C II and General Formation Properties of the C II Lines at 133.5 nm
Carlsson, Mats; Rathore, Bhavna
The C ii 133.5 {nm} lines are important observables for the NASA/SMEX mission Interface Region Imaging Spectrograph. To make three-dimensional (3D) non-LTE radiative transfer computationally feasible, it is crucial to have a model atom with as few levels as possible while retaining the main physical processes. We here develop such a model atom and…
Magnetic Untwisting in Solar Jets that Go into the Outer Corona in Polar Coronal Holes
Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.
We study 14 large solar jets observed in polar coronal holes. In EUV movies from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), each jet appears similar to most X-ray jets and EUV jets that erupt in coronal holes; but each is exceptional in that it goes higher than most, so high that it is observed in the outer corona beyond 2.…
The Absence of an Environmental Dependence in the Mass-Metallicity Relation at z = 2
Kewley, Lisa J.; Kacprzak, Glenn G.; Glazebrook, Karl +10 more
We investigate the environmental dependence of the mass-metallicity relation at z = 2 with MOSFIRE/Keck as part of the ZFIRE survey. Here, we present the chemical abundance of a Virgo-like progenitor at z = 2.095 that has an established red sequence. We identified 43 cluster (< z> =2.095+/- 0.004) and 74 field galaxies (< z> =2.195+/- …
[O I] 63 µm Jets in Class 0 Sources Detected By Herschel
Eislöffel, J.; Codella, C.; van Dishoeck, E. F. +9 more
We present Herschel PACS mapping observations of the [O i] 63 µm line toward protostellar outflows in the L1448, NGC 1333-IRAS4, HH 46, BHR 71, and VLA 1623 star-forming regions. We detect emission spatially resolved along the outflow direction, which can be associated with a low-excitation atomic jet. In the L1448-C, HH 46 IRS, and BHR 71 I…
Chromospheric Evaporation in an X1.0 Flare on 2014 March 29 Observed with IRIS and EIS
Ding, M. D.; Li, Y.; Qiu, J. +1 more
Chromospheric evaporation refers to dynamic mass motions in flare loops as a result of rapid energy deposition in the chromosphere. These motions have been observed as blueshifts in X-ray and extreme-ultraviolet (EUV) spectral lines corresponding to upward motions at a few tens to a few hundreds of km s-1. Past spectroscopic observation…
Spectral State Dependence of the 0.4-2 MeV Polarized Emission in Cygnus X-1 Seen with INTEGRAL/IBIS, and Links with the AMI Radio Data
Grinberg, Victoria; Pottschmidt, Katja; Wilms, Jörn +6 more
Polarization of the ≳ 400 keV hard tail of the microquasar Cygnus X-1 has been independently reported by INTEGRAL/Imager on Board the INTEGRAL Satellite (IBIS), and INTEGRAL/SPectrometer on INTEGRAL and interpreted as emission from a compact jet. These conclusions were, however, based on the accumulation of all INTEGRAL data regardless of the spec…
A Uniform Contribution of Core-collapse and Type Ia Supernovae to the Chemical Enrichment Pattern in the Outskirts of the Virgo Cluster
Simionescu, A.; Allen, S. W.; Werner, N. +3 more
We present the first measurements of the abundances of α-elements (Mg, Si, and S) extending out beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intracluster medium is consistent with being constant on large scales, with a flat d…