Publications (39)
A compact starburst ring traced by clumpy OH megamaser emission
R. Parra, J. E. Conway, M. Elitzur +1
We model the OH megamaser emission from the luminous infrared galaxy IIIZw35 as arising from a narrow rotating starburst ring of radius 22 pc enclosing a mass of 7 x 10^6 Msun. We…
Unveiling the nature of Seyfert nuclei with 1 - 100 micron spectral energy distributions
C. L. Buchanan, J. F. Gallimore, C. P. O'Dea +8
The infrared is a key wavelength regime for probing the dusty, obscured nuclear regions of active galaxies. We present results from an infrared study of 87 nearby Seyfert galaxies…
Infrared Spectral Energy Distributions of Seyfert Galaxies: Spitzer Space Telescope Observations of the 12 micron Sample of Active Galaxies
J. F. Gallimore, A. Yzaguirre, J. Jakoboski +8
The mid-far-infrared spectral energy distributions (SEDs) of 83 active galaxies, mostly Seyfert galaxies, selected from the extended 12 micron sample are presented. The data were c…
Detached shells as tracers of AGB-ISM bow shocks
C. J. Wareing, Albert A. Zijlstra, Angela K. Speck +10
New Spitzer imaging observations have revealed the structure around the Mira variable star R Hya to be a one-sided parabolic arc 100 arcsec to the West stretching from North to Sou…
Gemini Mid-IR Polarimetry of NGC1068: Polarized Structures Around the Nucleus
C. Packham, S. Young, R. S. Fisher +7
We present diffraction limited, 10um imaging polarimetry data for the central regions of the archetypal Seyfert AGN, NGC1068. The position angle of polarization is consistent with…
MOLPOP-CEP: An Exact, Fast Code for Multi-Level Systems
A. Asensio Ramos, M. Elitzur
We present MOLPOP-CEP, a universal line transfer code that allows the exact calculation of multi-level line emission from a slab with variable physical conditions for any arbitrary…
Bipolar outflow on the Asymptotic Giant Branch - the case of IRC+10011
D. Vinkovic, Th. Bloecker, K. -H. Hofmann +2
Near-IR imaging of the AGB star IRC+10011 (= CIT3) reveals the presence of a bipolar structure within the central ~0.1 arcsec of a spherical dusty wind. We show that the image asym…
Detection of a Far-Infrared Bow-Shock Nebula Around R Hya: the First MIRIAD Results
T. Ueta, A. K. Speck, R. E. Stencel +10
We present the first results of the MIRIAD (MIPS [Multiband Imaging Photometer for Spitzer] Infra-Red Imaging of AGB [asymptotic giant branch] Dustshells) project using the Spitzer…
The Mid-Infrared Emission of M87
E. S. Perlman, R. E. Mason, Christopher Packham +6
We discuss Subaru and Spitzer Space Telescope imaging and spectroscopy of M87 in the mid-infrared from 5-35 um. These observations allow us to investigate mid-IR emission mechanism…
An Investigation into the Effects of Luminosity on the Mid-Infrared Spectral Energy Distributions of Radio-Quiet Quasars
S. C. Gallagher, G. T. Richards, M. Lacy +3
We present an analysis of the effects of luminosity on the shape of the mid-infrared spectral energy distributions (SEDs) of 234 radio-quiet quasars originally presented by Richard…
Mid-IR Galaxy Classification Based on Silicate Obscuration and PAH Equivalent Width
H. W. W. Spoon, J. A. Marshall, J. R. Houck +5
We present a new diagnostic diagram for mid-infrared spectra of infrared galaxies based on the equivalent width of the 6.2 micron PAH emission feature and the strength of the 9.7 m…
W Hya through the eye of Odin Satellite observations of circumstellar submillimetre HO line emission
K. Justtanont, P. Bergman, B. Larsson +10
We present Odin observations of the AGB star W Hya in the ground-state transition of ortho-H2O, 1(10)-1(01), at 557GHz. The line is clearly of circumstellar origin. Radiative trans…
The dusty tori of nearby QSOs as constrained by high-resolution mid-IR observations
M. MartÃnez-Paredes, I. Aretxaga, A. Alonso-Herrero +13
We present mid-infrared (MIR, 7.5-13.5 m) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4m Gran Telescopio CANARIAS for a sample o…
Outflows from the high-mass protostars NGC 7538 IRS1/2 observed with bispectrum speckle interferometry -- Signatures of flow precession
S. Kraus, Y. Balega, M. Elitzur +6
NGC 7538 IRS1 is a high-mass (approx. 30 M_sun) protostar with a CO outflow, an associated UCHII region, and a linear methanol maser structure, which might trace a Keplerian-rotati…
Spatially-resolved mid-infrared spectroscopy of NGC 1068: the nature and distribution of the nuclear material
R. E. Mason, T. R. Geballe, C. Packham +4
We present spatially-resolved, near-diffraction-limited 10 micron spectra of the nucleus of the Seyfert 2 galaxy NGC 1068, obtained with Michelle, the mid-IR imager and spectromete…
Imaging the heart of astrophysical objects with optical long-baseline interferometry
J. -P. Berger, F. Malbet, F. Baron +21
The number of publications of aperture-synthesis images based on optical long-baseline interferometry measurements has recently increased due to easier access to visible and infrar…
A deep look at the nuclear region of UGC 5101 through high angular resolution mid-IR data with GTC/CanariCam
M. MartÃnez-Paredes, A. Alonso-Herrero, I. Aretxaga +13
We present an analysis of the nuclear infrared (IR, 1.6 to 18 m) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN)…
Detections of water ice, hydrocarbons, and 3.3um PAH in z~2 ULIRGs
A. Sajina, H. Spoon, L. Yan +3
We present the first detections of the 3um water ice and 3.4um amorphous hydrocarbon (HAC) absorption features in z~2 ULIRGs. These are based on deep rest-frame 2-8um Spitzer IRS s…
Deep Mid-Infrared Silicate Absorption as a Diagnostic of Obscuring Geometry Toward Galactic Nuclei
N. A. Levenson, M. M. Sirocky, L. Hao +4
The silicate cross section peak near 10um produces emission and absorption features in the spectra of dusty galactic nuclei observed with the Spitzer Space Telescope. Especially in…
A thin ring model for the OH megamaser in IIIZw35
R. Parra, J. E. Conway, M. Elitzur
We present a model for the OH megamaser emission in the starburst galaxy IIIZw35. The observed diffuse and compact OH maser components in this source are explained by a single phas…
Spectral line and continuum radiation propagation in a clumpy medium
J. E. Conway, M. Elitzur, R. Parra
We discuss the propagation of spectral line and continuum radiation in a clumpy medium and give general expressions for the observed absorption or emission from a cloud population.…
The central molecular gas structure in LINERs with low luminosity AGN: evidence for gradual disappearance of the torus
F. Müller-Sánchez, M. A. Prieto, M. Mezcua +3
We present observations of the molecular gas in the nuclear environment of three prototypical low luminosity AGN (LLAGN), based on VLT/SINFONI AO-assisted integral-field spectrosco…
Silicates in Ultra-Luminous Infrared Galaxies
M. M. Sirocky, N. A. Levenson, M. Elitzur +2
We analyze the mid-infrared (MIR) spectra of ultraluminous infrared galaxies (ULIRGs) observed with the Spitzer Space Telescope's Infrared Spectrograph. Dust emission dominates the…
Spitzer/IRS Observations of Seyfert 1.8s and 1.9s: A Comparison with Seyfert 1s and Seyfert 2s
R. P. Deo, D. M. Crenshaw, S. B. Kraemer +4
We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 um region. We compare the spectral characteristics of this sample to those…
Observational evidence for the shrinking of bright maser spots
A. M. S. Richards, M. Elitzur, J. A. Yates
The nature of maser emission means that the apparent angular size of an individual maser spot is determined by the amplification process as well as by the instrinsic size of the em…
The Most Detailed Picture Yet of an Embedded High-mass YSO
L. J. Greenhill, M. J. Reid, C. J. Chandler +2
High-mass star formation is not well understood chiefly because examples are deeply embedded, relatively distant, and crowded with sources of emission. Using VLA and VLBA observati…
A differentially rotating disc in a high-mass protostellar system
M. Pestalozzi, M. Elitzur, J. Conway
A strong signature of a circumstellar disc around a high-mass protostar has been inferred from high resolution methanol maser observations in NGC7538-IRS1 N. This interpretation ha…
The Flaring H2O Megamaser and Compact Radio Source in Mrk 348
A. B. Peck, C. Henkel, J. S. Ulvestad +5
We report on single-dish monitoring and extremely high angular resolution observations of the flaring H2O megamaser in the Seyfert 2 galaxy Mrk 348. The H2O line is redshifted by ~…
Dust and PAH emission in the star-forming active nucleus of NGC 1097
R. E. Mason, N. A. Levenson, C. Packham +4
The nucleus of the nearby galaxy, NGC 1097, is known to host a young, compact (r < 9 parsec) nuclear star cluster as well as a low-luminosity active galactic nucleus (AGN). It has…
Dust Emission from Active Galactic Nuclei
M. Nenkova, Z. Ivezic, M. Elitzur
Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to Seyfert 1 line spectrum for pole-on viewing and Seyfert 2…
Stellar Outflows Driven by Radiation Pressure
Z. Ivezic, G. R. Knapp, M. Elitzur
We present a detailed, self-consistent model of radiatively driven stellar outflows which couples the radiative transfer and hydrodynamics equations. The circumstellar envelope, wh…
NG7538 IRS1 N: modeling a circumstellar maser disk
M. R. Pestalozzi, M. Elitzur, J. Conway +1
We present an edge-on Keplerian disk model to explain the main component of the 12.2 and 6.7 GHz methanol maser emission detected toward NGC7538-IRS1 N. The brightness distribution…
An embedded active nucleus in the OH megamaser galaxy IRAS16399-0937
Dinalva A. Sales, A. Robinson, D. J. Axon +7
We present a multiwavelength study of the OH Megamaser galaxy (OHMG) IRAS16399-0937, based on new HST/ACS F814W and H+[NII] images and archive data from HST, 2MASS, Spitzer, He…
Estimations of the magnetic field strength in the torus of AGN using near-infrared polarimetry
E. Lopez-Rodriguez, C. Packham, S. Young +7
An optically and geometrically thick torus obscures the central engine of Active Galactic Nuclei (AGN) from some lines of sight. From a magnetohydrodynamical framework, the torus c…
Evidence for bipolar jets in late stages of AGB winds
D. Vinkovic, M. Elitzur, K. -H. Hofmann +1
Bipolar expansion at various stages of evolution has been recently observed in a number of AGB stars. The expansion is driven by bipolar jets that emerge late in the evolution of A…
The Nuclear Infrared Emission of Low-Luminosity Active Galactic Nuclei
R. E. Mason, E. Lopez-Rodriguez, C. Packham +9
We present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs) and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGN…
The distribution of silicate strength in Spitzer spectra of AGNs and ULIRGs
Lei Hao, D. W. Weedman, H. W. W. Spoon +4
A sample of 196 AGNs and ULIRGs observed by the Infrared Spectrograph (IRS) on Spitzer is analyzed to study the distribution of the strength of the 9.7 micron silicate feature. Ave…
Dust Emission from Herbig Ae/Be stars - Evidence for Disks and Envelopes
A. Miroshnichenko, Z. Ivezic, D. Vinkovic +1
IR and mm-wave emission from Herbig Ae/Be stars has produced conflicting conclusions regarding the dust geometry in these objects. We show that the compact dimensions of the mm-wav…
The Nature of Deeply Buried Ultraluminous Infrared Galaxies: A Unified Model for Highly Obscured Dusty Galaxy Emission
J. A. Marshall, M. Elitzur, L. Armus +2
We present models of deeply buried ultraluminous infrared galaxy (ULIRG) spectral energy distributions (SEDs) and use them to construct a three-dimensional diagram for diagnosing t…