Past Events in 2019

Extending our Vision to a Galaxy of Planets

Date: 
Wednesday, May 01, 2019 - 3:30pm PDT
Speaker: 
Karl Stapelfeldt
Affiliation: 
JPL
Location: 
N232 R103
Event Type: 
Colloquium

The most obvious method of studying extrasolar planets - directly imaging them alongside their parent star - is also the most difficult. Image contrasts exceeding a billion to one, at subarcsecond separations, are required to detect an analog of our solar system in reflected starlight. Following the charge of the Astro2010 decadal survey, the NASA Exoplanet Exploration Program (ExEP) is tasked with developing the technology and precursor science needed to realize the goals of directly imaging Earth analogs and characterizing their atmospheres for habitability and the presence of life.

HAWC+ Observations of OMC-1

Date: 
Wednesday, May 08, 2019 - 9:00am PDT
Speaker: 
David Chuss
Affiliation: 
Villanova University
Location: 
N/A
Event Type: 
Teletalk

Far-Infrared polarimetry is a useful tool for exploring the role of magnetic fields in star formation. The HAWC+/SOFIA polarimeter provides a major leap forward in observing capability from previous FIR polarimeters. HAWC+ has mapped OMC-1 in all four bands both photometrically and polarimetrically. In this talk, I will review the results of the HAWC+ Science Team’s publication on these data.  We provide improved maps for SED fit parameters of the region, including column density and temperature.

Frontiers of Radio Astronomy: The next-generation Very Large Array

Date: 
Wednesday, May 08, 2019 - 3:30pm PDT
Speaker: 
Eric Murphy
Affiliation: 
NRAO
Location: 
N232 R103
Event Type: 
Colloquium

Inspired by dramatic discoveries from the Jansky VLA, VLBA, and ALMA, a plan to pursue a large collecting area radio interferometer that will open new discovery space from proto-planetary disks to distant galaxies is being developed by NRAO and the international science community.  Building on the superb cm observing conditions and existing infrastructure of the VLA site in the U.S. Southwest, the current vision of the ngVLA will be an interferometric array with more than 10 times the sensitivity and spatial resolution of the current VLA and ALMA, operating at frequencies spanning ~1.2.

Star Formation in the Galactic Center: The Role of Radiative Feedback

Date: 
Wednesday, May 15, 2019 - 3:30pm PDT
Speaker: 
Fabian Heitsch
Affiliation: 
UNC
Location: 
N232 R103
Event Type: 
Colloquium

The presence of young, massive stars suggests a substantial mass inflow event to the Galactic Center approximately 6 million years ago. Numerical models of gas inflow toward a supermassive black hole show that star formation may occur in such an environment through the growth of a gravitationally unstable gas disc of high eccentricity. As a refinement on previous calculations, our models include the effects of radiative feedback on disk and star formation during such an accretion episode.

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): The Infrared at High Angular Resolution

Date: 
Wednesday, May 22, 2019 - 3:30pm PDT
Speaker: 
Stephen Rinehart
Affiliation: 
NASA Goddard
Location: 
N232 R103
Event Type: 
Colloquium

Infrared observations have provided critical information for understanding the processes by which stars form. Much of this understanding is derived from observations of low-mass protostars forming in relative isolation, and yet the majority of stars in our galaxies have formed in dense clusters. Unfortunately, while a panoply of different facilities have been used to explore these clusters, there remains a critical gap in the observations — spatially-resolved spectroscopy.   The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is designed to fill this gap.

First Astrophysical Detection of the Helium Hydride Ion (HeH+)

Date: 
Wednesday, June 05, 2019 - 9:00am PDT
Speaker: 
David Neufeld
Affiliation: 
Johns Hopkins University
Location: 
N/A
Event Type: 
Teletalk

The helium hydride ion, HeH+, has been detected in space for the first time with the use of the GREAT spectrometer on SOFIA. Through observations of its fundamental rotational transition at 2.010 THz (149.1 micron), HeH+ was detected toward the young planetary nebula NGC 7027. This detection brings a three-decades-long search to a successful conclusion.

Unraveling the Evolution of the Interstellar Medium and Star Formation in the M51 Grand-Design Spiral Galaxy with SOFIA

Date: 
Wednesday, June 12, 2019 - 9:00am PDT
Speaker: 
Jorge Pineda
Affiliation: 
JPL
Location: 
N/A
Event Type: 
Teletalk

We present results on a joint impact project to map the entire extent of the M51 grand-design spiral galaxy in the [CII] 158um line with the upGREAT and FIFI-LS instruments on SOFIA. The [CII] 158um line is an important tool to diagnose the physical state of the ISM as it can reveal the distribution of the gas that is in the transition between atomic and molecular phases, including the CO-dark H2 gas (hydrogen is molecular, but carbon is not, resulting in this gas being traced neither by CO nor by HI). Additionally, the [CII] line is an important tracer of star formation in galaxies.

Black Hole Masses in Active Galaxies

Date: 
Friday, June 14, 2019 - 3:00pm PDT
Speaker: 
Misty Bentz
Affiliation: 
Georgia State
Location: 
N232 R103
Event Type: 
Colloquium

One of the legacy results of the Hubble Space Telescope is the discovery that supermassive black holes inhabit the centers of all massive galaxies, and these black holes appear to have a symbiotic relationship with their host galaxies.  One of the keys to understanding this relationship involves constraining the masses of the black holes. However, black hole mass measurements are difficult to achieve because they require direct observations of the invisible black hole's gravitational influence on luminous tracers (stars or gas).

Understanding the chemistry of Phosphorus, the missing pre-biotic element, in star-forming regions

Date: 
Friday, June 21, 2019 - 3:00pm PDT
Speaker: 
Francesco Fontani
Affiliation: 
Arcetri Observatory
Location: 
N232 R103
Event Type: 
Colloquium

Phosphorus is a crucial element for the development of life as we know it, but because of its low abundance, until recently its interstellar chemistry was almost totally unknown. Since 2016, the star formation group at Arcetri has made a fundamental contribution to our understanding of the astrochemical processes that involve this element in the star-forming regions of the Galaxy, paving the way for a growing number of studies on this pre-biotic element that had been “forgotten” up to now.

Ocean-Like Water in Hyperactive Comets

Date: 
Wednesday, July 10, 2019 - 9:00am PDT
Speaker: 
Dariusz Lis
Affiliation: 
Caltech
Location: 
N/A
Event Type: 
Teletalk

The deuterium-to-hydrogen ratio in cometary water has been shown to vary between 1 and 3 times the Earth’s oceans value, in both Oort cloud comets and Jupiter-family comets originating from the Kuiper belt. This has been taken as evidence that comets contributed a relatively small fraction of the terrestrial water. New sensitive spectroscopic observations of the Jupiter-family comet 46P/Wirtanen carried out using the GREAT spectrometer aboard SOFIA lead to a D/H ratio of (1.61±0.65)×10−4, the same as in the Earth’s oceans.

Planetary Collisions in a Binary Star System? Studying the Evolution of Warm Dust Encircling BD +20 307 Using SOFIA

Date: 
Wednesday, July 17, 2019 - 9:00am PDT
Speaker: 
Maggie Thompson
Affiliation: 
University of California, Santa Cruz
Location: 
N/A
Event Type: 
Teletalk

The small class of known stars with unusually warm, dusty debris disks is a key sample to probe in order to understand cascade models and the extreme collisions that likely lead to the final configurations of planetary systems. Because of its extreme dustiness and small radius, the disk around the binary star system BD +20 307 has a short predicted collision time and is therefore an interesting target in which to look for changes in dust quantity and composition over time.

SOFIA FORCAST Photometry of 12 Extended Green Objects in the Milky Way

Date: 
Wednesday, August 07, 2019 - 9:00am PDT
Speaker: 
Allison Towner
Affiliation: 
University of Virgnia, NRAO
Location: 
N/A
Event Type: 
Teletalk

Massive young stellar objects (MYSOs) are known to undergo an evolutionary phase in which high mass accretion rates drive strong outflows. A class of objects believed to trace this phase accurately is the Spitzer GLIMPSE Extended Green Object (EGO) sample, so named for the presence of extended 4.5 um emission on size scales of ~0.1 pc in Spitzer images. We have been conducting a multiwavelength examination of a sample of 12 EGOs with distances of 1 to 5 kpc.

The Origin of [CII] 158µm Emission Toward the HII Region Complex S235

Date: 
Wednesday, August 14, 2019 - 9:00am PDT
Speaker: 
Loren Anderson
Affiliation: 
West Virginia University
Location: 
N/A
Event Type: 
Teletalk

Although the 2P3/2-2P1/2 transition of [CII] at 158µm is known to be an excellent tracer of active star formation, we still do not have a complete understanding of where within star formation regions the emission originates. We use SOFIA upGREAT observations of [CII] emission toward the HII region complex Sh2-235 (S235) to better understand in detail the origin of [CII] emission. We complement these data with a fully-sampled Green Bank Telescope radio recombination line map tracing the ionized hydrogen gas.

SOFIA’s Vision for the Future

Date: 
Wednesday, September 04, 2019 - 9:00am PDT
Speaker: 
Hal Yorke
Affiliation: 
SOFIA/USRA
Location: 
N/A
Event Type: 
Teletalk

SOFIA has recently been the subject of two major back-to-back reviews: The SOFIA Operations and Maintenance Efficiency Review (SOMER) and the SOFIA 5-Year Flagship Mission Review (FMR). For the SOMER, a team of experts in operating and maintaining aircraft looked at these aspects of the SOFIA program, whereas for the FMR, a separate panel (of scientists augmented by two members of the SOMER team) thoroughly reviewed science operations and SOFIA’s future science outlook.

POLSTAR survey: Magnetic fields in Pristine to Cluster Forming Filaments

Date: 
Wednesday, September 11, 2019 - 3:30pm PDT
Speaker: 
Thushara Pillai
Affiliation: 
Boston University
Location: 
N232 R103
Event Type: 
Colloquium

Massive, cold, dense filaments, often appearing as infrared dark clouds (IRDCs), are the nurseries of massive stars. No measurements of magnetic fields in IRDCs in a state prior to the onset of high-mass star formation (HMSF) have previously been available, and prevailing HMSF theories do not consider strong magnetic fields.Our recent polarization observations show that massive filaments are strongly magnetized and that the strong magnetic field is as important as turbulence and gravity for HMSF.

The Far-Infrared Polarization Spectrum of Rho Ophiuchi A from HAWC+/SOFIA Observations

Date: 
Wednesday, September 18, 2019 - 9:00am PDT
Speaker: 
Fabio Santos
Affiliation: 
MPIfA
Location: 
N/A
Event Type: 
Teletalk

In this work (recently accepted for publication at ApJ), we report on polarimetric maps made with HAWC+/SOFIA toward Rho Ophiuchi, the densest portion of the Rho Ophiuchi molecular complex. We employed HAWC+ bands C (89 microns) and D (154 microns). The slope of the polarization spectrum was investigated by defining the quantity R_DC = p_D/p_C, where p_C and p_D represent polarization degrees in bands C and D, respectively. We find a clear correlation between R_DC and the molecular hydrogen column density across the cloud.

Far-infrared [O III] and [O I] Observations of CO-knots in Cas A

Date: 
Wednesday, October 02, 2019 - 9:00am PDT
Speaker: 
Jeonghee Rho
Affiliation: 
SETI Institute
Location: 
N/A
Event Type: 
Teletalk

Dense, fast-moving ejecta knots in supernova remnants are prime sites for molecule and dust formation. We present SOFIA far-IR spectrometer FIFI-LS observations of CO-rich knots in Cas A in the [O III] 52 and 88-micron and [O I] 63-micron lines. The [O I] map shows bright emission associated with the dense CO-rich knots and traces cooled, dense post-shocked gas of ejecta. In contrast, the [O III] maps reveal diffuse, larger-scale structures and the ratio of the two [O III] lines provide a density map.

The Hidden Baryons of the Milky Way

Date: 
Wednesday, October 02, 2019 - 3:30pm PDT
Speaker: 
Yong Zheng
Affiliation: 
UC Berkeley
Location: 
N232 R103
Event Type: 
Colloquium

Galaxies are not lonely islands floating in the Universe. They host large gaseous envelopes of baryons, a.k.a., the circum-galactic medium (CGM), that exist far beyond a galaxy’s visible extent. Baryonic inflows from CGM replenish star-forming fuel in galaxies, whereas outflows from galaxies enrich the CGM. In this talk, I will describe the theoretical and observed distribution and flows of baryons in the CGM of our own Milky Way (MW), including how the MW’s disk hides up to half of its CGM from direct observation.

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