Joseph Jensen | Utah Valley University (original) (raw)

Papers by Joseph Jensen

Symposium - International Astronomical Union, 1991

Lindsay 11 and NGC 1806 are globular clusters in the Small and Large Magellanic Clouds (SMC and L... more Lindsay 11 and NGC 1806 are globular clusters in the Small and Large Magellanic Clouds (SMC and LMC) respectively. Both clusters have extended asymptotic giant branches with carbon stars at the tip. Colour-magnitude diagrams are fitted with appropriate isochrones which indicate that both clusters belong to the abundant population of intermediate age in the Magellanic Clouds.

The Astrophysical Journal

With Cosmicflows-4, distances are compiled for 55,877 galaxies gathered into 38,065 groups. Eight... more With Cosmicflows-4, distances are compiled for 55,877 galaxies gathered into 38,065 groups. Eight methodologies are employed, with the largest numbers coming from the correlations between the photometric and kinematic properties of spiral galaxies (TF) and elliptical galaxies (FP). Supernovae that arise from degenerate progenitors (type Ia SNe) are an important overlapping component. Smaller contributions come from distance estimates from the surface brightness fluctuations of elliptical galaxies and the luminosities and expansion rates of core-collapse supernovae (SNe II). Cepheid period–luminosity relation and tip of the red giant branch observations founded on local stellar parallax measurements along with the geometric maser distance to NGC 4258 provide the absolute scaling of distances. The assembly of galaxies into groups is an important feature of the study in facilitating overlaps between methodologies. Merging between multiple contributions within a methodology and between ...

HAL (Le Centre pour la Communication Scientifique Directe), Oct 14, 2022

arXiv (Cornell University), Sep 22, 2022

ATel, Jun 1, 2002

V. M. Kaspi (McGill University/Massachusetts Institute of Technology), J. Jensen (Gemini), F. Rig... more V. M. Kaspi (McGill University/Massachusetts Institute of Technology), J. Jensen (Gemini), F. Rigaut (Gemini), A. Hatakeyama (Gemini), P. M. Woods (USRA/NSSTC) report Gemini North 8-m near-IR observations of the anomalous X-ray pulsar 1E 2259+586 field. K_s band data were obtained on June 21, 2002 at 14:44 UT using the NIRI instrument and a 30-min exposure with seeing 0.7".

Proceedings of SPIE, Jul 12, 2008

Gemini's instrument program, which has existed for about a decade, has recently produced enough i... more Gemini's instrument program, which has existed for about a decade, has recently produced enough instruments to fully populate all of the instrument ports on both Gemini-N and Gemini-S. These delivered instruments, as well as those currently under construction and due to be delivered in the next ~2 years, are described in this report. We also summarize the bold new directions Gemini's development program will go in the next 5-10 years, as our Community embarks upon a new science mission to answer some of the most fundamental questions in astronomy.

Proceedings of SPIE, Jun 14, 2006

First, a status report is given for the on-going (Phase 2) instruments under construction now for... more First, a status report is given for the on-going (Phase 2) instruments under construction now for Gemini. These instruments will be deployed during 2006 and 2007 at Gemini-South and collectively represent the end of an era of instrument building within the Gemini ...

The Astrophysical Journal, May 11, 2016

We present new Hubble Space Telescope (HST) optical and near-infrared (NIR) photometry of the ric... more We present new Hubble Space Telescope (HST) optical and near-infrared (NIR) photometry of the rich globular cluster (GC) system of NGC 4874, the cD galaxy in the core of the Coma cluster (Abell 1656). NGC 4874 was observed with the HST Advanced Camera for Surveys in the F475W (g 475) and F814W (I 814) passbands and the Wide Field Camera 3 IR Channel in F160W (H 160). The GCs in this field exhibit a bimodal optical color distribution with more than half of the GCs falling on the red side at g 475 −I 814 > 1. Bimodality is also present, though less conspicuously, in the optical-NIR I 814 −H 160 color. Consistent with past work, we find evidence for nonlinearity in the g 475 −I 814 versus I 814 −H 160 color-color relation. Our results thus underscore the need for understanding the detailed form of the color-metallicity relations in interpreting observational data on GC bimodality. We also find a very strong color-magnitude trend, or "blue tilt," for the blue component of the optical color distribution of the NGC 4874 GC system. A similarly strong trend is present for the overall mean I 814 −H 160 color as a function of magnitude; for M 814 < −10 mag, these trends imply a steep mass-metallicity scaling with Z ∝ M 1.4±0.4 GC , but the scaling is not a simple power law and becomes much weaker at lower masses. As in other similar systems, the spatial distribution of the blue GCs is more extended than that of the red GCs, partly because of blue GCs associated with surrounding cluster galaxies. In addition, the center of the GC system is displaced by 4 ± 1 kpc towards the southwest from the luminosity center of NGC 4874, in the direction of NGC 4872. Finally, we remark on a dwarf elliptical galaxy with a noticeably asymmetrical GC distribution. Interestingly, this dwarf has a velocity of nearly −3000 km s −1 with respect to NGC 4874; we suggest it is on its first infall into the cluster core and is undergoing stripping of its GC system by the cluster potential.

AAS, 2014

ABSTRACT We estimate the luminosity-weighted ages of 16 early-type galaxies in Virgo and Fornax c... more ABSTRACT We estimate the luminosity-weighted ages of 16 early-type galaxies in Virgo and Fornax clusters based upon the near-IR (F110W and F160W) SBF observations using the Hubble Space Telescope (HST). We compare the HST observations with the stellar population synthesis models using the Padova and the Teramo isochrones, respectively. We investigate and present how the alpha-element enhancement and the convective core overshoot affect the mean age and star formation history estimation.

Astrophysical Journal Supplement Series, May 1, 1988

Four LMC star clusters are examined whose colors suggest ages between 2 and 10 Gyr. Three of thes... more Four LMC star clusters are examined whose colors suggest ages between 2 and 10 Gyr. Three of these, NGC 1754, NGC 1795 and SL 506, have ages within the well-populated range from 0.8 to 3 Gyr. No conclusion can be reached about the age of NGC 2005, which is located in the Bar and very crowded. No cluster has yet

Astrophysical Journal Supplement Series, Oct 1, 1992

ABSTRACT

American Astronomical Society Meeting Abstracts #225, 2015

arXiv (Cornell University), Nov 20, 1999

Complete samples of ultraluminous infrared galaxies (ULIGs 1) have been imaged at R-band and K-ba... more Complete samples of ultraluminous infrared galaxies (ULIGs 1) have been imaged at R-band and K-band from Mauna Kea. Here we present a preliminary analysis of the host galaxy magnitudes and the 1-D radial profiles for a subset of objects in the IRAS 1-Jy sample of ULIGs (z < 0.3), and compare these properties with recently published data for "low-z" QSOs. ULIGs in the 1-Jy sample reside in luminous hosts, with mean luminosities ∼ 2.

American Astronomical Society Meeting Abstracts #225, 2015

With measuring accurate distances to nearby galaxies using surface brightness fluctuations (SBF),... more With measuring accurate distances to nearby galaxies using surface brightness fluctuations (SBF), we can further our knowledge of the size, expansion rate, and age of the Universe. The Coma cluster is an important cluster for which there are several existing distance measurements, including a recent one using Cepheid variable stars in the spiral galaxy NGC 4921. Despite the fact that SBF analysis is not typically reliable for spiral galaxies, we were able to do SBF analysis on NGC 4921 using images gathered from the Space Telescope archive. Optical images in the I and r filters were cleaned and combined to make two separate images of NGC 4921. We also measured the SBF distance to the central giant elliptical galaxy NGC 4874 using Space Telescope infrared images. The result of this work was a SBF distance measurement that will help us calculate the distance to the Coma cluster and understand the properties of the stars in these galaxies. We then compare the Cepheid and SBF distances to the Coma cluster to yield a new measurement of the relative distance between the Virgo and Coma clusters.

AAS, 2015

Surface brightness fluctuaHons (SBF) are a useful tool for measuring extragalacHc distances. At i... more Surface brightness fluctuaHons (SBF) are a useful tool for measuring extragalacHc distances. At infrared wavelengths, SBF break the age-metallicity degeneracy and are useful for probing the properHes of the most luminous stars in a galaxy, even when individual stars are not resolved. We present a detailed comparison of F110W and F160W SBF measurements made using the Hubble Space Telescope WFC3/IR camera to a variety of stellar populaHon models, including those with solar-scaled and alpha-enhanced composiHons and models incorporaHng convecHve core overshoot for younger populaHons. We use these model comparisons to assess the star formaHon histories of 6 galaxies spanning a wide range in color and luminosity in the Virgo and Fornax clusters, measured as a funcHon of distance from the galaxy center in ellipHcal apertures. We discuss the implicaHons of populaHon variaHons on the fluctuaHon magnitudes and distance measurements.

We measured Surface Brightness FluctuaIons (SBF) in three galaxies, ESO137-G006, NGC 3309, and NG... more We measured Surface Brightness FluctuaIons (SBF) in three galaxies, ESO137-G006, NGC 3309, and NGC 5128, using the GeMS MulIConjugate AdapIve OpIcs (MCAO) system on the Gemini South telescope. ESO137-G006 is located in the Norma Cluster, NGC 3309 is located in the Hydra Cluster, while NGC 5128, also known as Centaurus A, is a nearby galaxy with numerous other distance measurements, including Cepheids. These galaxies were observed as a path finder to establish the SBF technique using the MCAO system. The J and Ks-band images taken with MCAO were astrometrically corrected and combined using the THELI so_ware.1 This method allowed us to accurately account for the distorIons of the focal plane when combining the images. The foreground stars as well as the globular clusters were measured to account for their contribuIon to the SBF. (J-Ks) color measurements were made to calibrate SBF and determine the stellar populaIons of the galaxies. The results of these measurements give us an SBF ca...

The Astrophysical Journal, 2020

We present the first measurement of the mass of a supermassive black hole (SMBH) in the nearby do... more We present the first measurement of the mass of a supermassive black hole (SMBH) in the nearby double-barred spiral galaxy NGC 3504 as part of the Measuring Black Holes Below the Milky Way (M) mass galaxies (MBHBM) Project. Our analysis is based on Atacama Large Millimeter/submillimeter Array (ALMA) Cycle-5 observations of the 12 CO(2 − 1) emission line. NGC 3504 has a circumnuclear gas disk (CND), which has a relatively high velocity dispersion of 30 km s −1. Our dynamical models of the CND yield a M BH of M BH = 1.02 +0.18 −0.15 × 10 7 M and a mass-to-light ratio in H-band of M/L H = 0.66 +1.44 −0.65 (M /L). This black hole (BH) mass is consistent with BH-galaxy scaling relations. We also detect a central deficiency in the 12 CO(2 − 1) integrated intensity map with a diameter of 2.7 pc at the putative position of the SMBH. However, this hole is filled by a dense gas tracer CS(5 − 4) that peaks at the galaxy center found in one of the three low-velocity-resolution continuum spectral correlators. The CS(5 − 4) line has the same kinematics with the 12 CO(2 − 1) line within the CND, suggesting that it is also an alternative transition for measuring the central M BH in NGC 3504 probably more accurately than the current commonly used of 12 CO(2 − 1) due to its centralization.

Symposium - International Astronomical Union, 1994

We present observations of the 11 July 1991 total solar eclipse made from the Caltech Submillimet... more We present observations of the 11 July 1991 total solar eclipse made from the Caltech Submillimeter Observatory. The 850 μm limb is extended 3380±140 km above the visible limb, and there is a 10% brightening at the extreme limb. The measured limb height agrees with previous work at shorter and longer wavelengths. The run of limb heights with wavelength is well fit by a single electron density scale height. We argue that there is no need to invoke spicule geometry to explain the observations.

The Astrophysical Journal, 2018

The joint detection of gravitational waves and electromagnetic radiation from the binary neutron ... more The joint detection of gravitational waves and electromagnetic radiation from the binary neutron star (BNS) merger GW170817 has provided unprecedented insight into a wide range of physical processes: heavy element synthesis via the r-process; the production of relativistic ejecta; the equation of state of neutron stars and the nature of the merger remnant; the binary coalescence timescale; and a measurement of the Hubble constant via the "standard siren" technique. In detail, all of these results depend on the distance to the host galaxy of the merger event, NGC 4993. In this paper we measure the surface brightness fluctuation (SBF) distance to NGC 4993 in the F110W and F160W passbands of the Wide Field Camera 3 Infrared Channel on the Hubble Space Telescope (HST). For the preferred F110W passband we derive a distance modulus of (m−M) = 33.05 ± 0.08 ± 0.10 mag, or a linear distance d = 40.7 ± 1.4 ± 1.9 Mpc (random and systematic errors, respectively); a virtually identical result is obtained from the F160W data. This is the most precise distance to NGC 4993 available to date. Combining our distance measurement with the corrected recession velocity of NGC 4993 implies a Hubble constant H 0 = 71.9 ± 7.1 km s −1 Mpc −1. A comparison of our result to the GW-inferred value of H 0 indicates a binary orbital inclination of i 137 deg. The SBF technique can be

Symposium - International Astronomical Union, 1991

The Astrophysical Journal

HAL (Le Centre pour la Communication Scientifique Directe), Oct 14, 2022

arXiv (Cornell University), Sep 22, 2022

ATel, Jun 1, 2002

Proceedings of SPIE, Jul 12, 2008

Proceedings of SPIE, Jun 14, 2006

The Astrophysical Journal, May 11, 2016

AAS, 2014

Astrophysical Journal Supplement Series, May 1, 1988

Astrophysical Journal Supplement Series, Oct 1, 1992

ABSTRACT

American Astronomical Society Meeting Abstracts #225, 2015

arXiv (Cornell University), Nov 20, 1999

American Astronomical Society Meeting Abstracts #225, 2015

AAS, 2015

The Astrophysical Journal, 2020

Symposium - International Astronomical Union, 1994

The Astrophysical Journal, 2018

The Great Observatories All-Sky LIRG Survey (GOALS 20) combines data from NASA's Spitzer Space Te... more The Great Observatories All-Sky LIRG Survey (GOALS 20) combines data from NASA's Spitzer Space Telescope, Chandra X-Ray Observatory, Hubble Space Telescope (HST), and Galaxy Evolution Explorer (GALEX) observatories, together with ground-based data, into a comprehensive imaging and spectroscopic survey of over 200 low-redshift (z < 0:088), Luminous Infrared Galaxies (LIRGs). The LIRGs are a complete subset of the IRAS Revised Bright Galaxy Sample (RBGS), which comprises 629 extragalactic objects with 60 μm flux densities above 5.24 Jy, and Galactic latitudes above five degrees. The LIRGs targeted in GOALS span the full range of nuclear spectral types defined via traditional optical line-ratio diagrams (type-1 and type-2 AGN, LINERs, and starbursts) as well as interaction stages (major mergers, minor mergers, and isolated galaxies). They provide an unbiased picture of the processes responsible for enhanced infrared emission in galaxies in the local Universe. As an example of the analytic power of the multiwavelength GOALS data set, we present Spitzer, Chandra, HST, and GALEX images and spectra for the interacting system VV 340 (IRAS F14547 þ 2449). The Spitzer MIPS imaging data indicates that between 80–95% of the total far-infrared emission (or about 5 × 10 11 L ⊙) originates in VV 340 north. While the Spitzer IRAC colors of VV 340 north and south are consistent with star-forming galaxies, both the Spitzer IRS and Chandra ACIS data indicate the presence of an AGN in VV 340 north. The observed line fluxes, without correction for extinction, imply that the AGN accounts for less than 10%–20% of the observed infrared emission. The X-ray data are consistent with a heavily absorbed (N H ≥ 10 24 cm À2) AGN. The GALEX far and near-UV fluxes imply a extremely large infrared " excess " (IRX) for the system (F IR =F fuv ∼ 81) which is well above the correlation seen in starburst galaxies. Most of this excess is driven by VV 340 N, which has an IR excess of nearly 400. The VV 340 system seems to be comprised of two very different galaxies: an infrared luminous edge-on galaxy (VV 340 north) that dominates the long-wavelength emission from the system, which hosts a buried AGN; and a face-on starburst (VV 340 south) that dominates the short-wavelength emission.