Accepted Cycle 21 Archive Proposals

Proposal Number	Subject Category	PI Name	Title
21200065	STARS AND WD	Michael Kuhn	Explaining iron K-alpha line emission from YSOs in Orion: analysis of simultaneous Chandra-NuSTAR observations
21200078	STARS AND WD	Joy Nichols	Catalog of Serendipitous Gratings Spectra
21200339	STARS AND WD	Javier García	A Complete 3D map of the Milky Way using X-rays: The Chandra and Gaia Synergy
21300106	WD BINARIES AND CV	Marina Orio	The Grating Spectra of nuclear burning white dwarfs
21300308	WD BINARIES AND CV	Robert Hynes	X-RAY SELECTED SYMBIOTIC BINARIES IN THE CHANDRA SOURCE CATALOG
21500527	SN, SNR AND ISOLATED NS	Tyler Holland-Ashford	Quantifying Heavy Element Asymmetries in SNRs with Chandra
21500563	SN, SNR AND ISOLATED NS	Oleg Kargaltsev	X-ray content of Galactic Fermi LAT 4FGL sources
21620305	NORMAL GALAXIES: X-RAY POPULATIONS	Mark Peacock	Do LMXB populations vary among old early-type galaxies?
21700098	ACTIVE GALAXIES AND QUASARS	Elena Gallo	Improved constraints to the local black hole occupation fraction
21700214	ACTIVE GALAXIES AND QUASARS	Tracey Turner	HETG and NuSTAR: toward a Global picture for the X-ray reprocessor in AGN
21700319	ACTIVE GALAXIES AND QUASARS	Adi Foord	Quantifying the Rate of Nearby Dual AGNs: Archival Sample
21700372	ACTIVE GALAXIES AND QUASARS	Cassandra Hatcher	Does Excess Mid-Infrared Emission Reliably Signal an AGN?
21700442	ACTIVE GALAXIES AND QUASARS	Chien-Ting Chen	TRACKING THE GROWTH OF MASSIVE BLACK HOLES IN THE PROGENITORS OF DWARF GALAXIES
21800432	CLUSTERS OF GALAXIES	Esra Bulbul	Constraining the Origin of Optical Filaments in the Perseus Cluster with a Novel Technique
21900326	EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS	Christine Jones	Exploring the Dawn of Supermassive Black Holes in Galaxy Cluster Lensing Fields
21910238	GALACTIC DIFFUSE EMISSION AND SURVEYS	Smita Mathur	Understanding the chemical enrichment and heating of the circumgalactic medium with observations of the Milky Way.
21910386	GALACTIC DIFFUSE EMISSION AND SURVEYS	Francesca Fornasini	Towards a complete classification of Galactic NuSTAR Sources with the Chandra Cool Attitude Target Program

Subject Category: STARS AND WD

Proposal Number: 21200065

Title: Explaining iron K-alpha line emission from YSOs in Orion: analysis of simultaneous Chandra-NuSTAR observations

PI Name: Michael Kuhn

We propose an archive study of the the 6.4 keV iron K-alpha line in young stellar objects (YSOs) based on simultaneous 90 ks Chandra and NuSTAR observations of the Orion Nebula Cluster. This line results when neutral iron in circumstellar disks is ionized by high energy X-rays from stellar coronae, allowing the interaction between the corona and disk to be probed. The joint Chandra/NuSTAR observations will cover 0.5-79 keV; Chandra will be used to localize the X-ray sources; and NuSTAR will provide information about both the 6.4 keV line and the high-energy X-rays above 7.1 keV that produce the ionization. We will statistically examine correlations between the 6.4 keV equivalent width and properties of X-ray emission and the circumstellar disk.

Subject Category: STARS AND WD

Proposal Number: 21200078

Title: Catalog of Serendipitous Gratings Spectra

PI Name: Joy Nichols

After the creation of the Chandra Source Catalog 2.0, there remains one important element of discovery space in the Chandra Archive. A search for serendipitous sources in gratings data can yield new high resolution spectra of a number of objects without bias as to the type of object detected. In these observations, all sources within the field of view are dispersed by the gratings, but only the spectrum of the primary target is available in the archived data products. We will utilize the CSC 2.0 when possible, and a detection algorithm in other fields to locate sources for possible spectral extraction. Multiple observations of the same field will yield multiple spectra for co-addition. This project is straighforward in concept because all the necessary tools are in place.

Subject Category: STARS AND WD

Proposal Number: 21200339

Title: A Complete 3D map of the Milky Way using X-rays: The Chandra and Gaia Synergy

PI Name: Javier García

The cold phase of the ISM, dominated by hydrogen, acts as a gas reservoir for the star formation processes. Thus, knowledge of the H density distribution in the Milky Way is key for the understanding its chemical evolution. We propose to characterize the spatial distribution of the H atoms and molecules in the ISM by modeling the X-ray spectra of all objects in the Chandra Sources Catalog (CSC). We will measure H columns by fitting the spectra, and and cross-match these sources with those in the Gaia DR2 catalog. By selecting the cases with accurate parallax measurements, we will produce a distance distribution of the H columns in multiple line-of-sights, and finally a detailed 3D map of the H distribution in the local ISM.

Subject Category: WD BINARIES AND CV

Proposal Number: 21300106

Title: The Grating Spectra of nuclear burning white dwarfs

PI Name: Marina Orio

I propose a comprehensive, comparative project using tens of spectra of white dwarfs undergoing steady nuclear burning in shell, and of post-outburst novae. My goals are: 1) Prepare a comprehensive list of unidentified lines for producers of atomic data, 2) Explore and analyse several data set that have never been published, comparing also non-nova sources (steady SSS or non-ejecting thermonuclear runaways) with the atmospheres of post-outburst novae, and 5) understand and model the root cause of the blue-shifted absorption lines, when the white dwarf seems to have shrunk back to almost the original radius and the bulk of mass ejection appears to have ceased.

Subject Category: WD BINARIES AND CV

Proposal Number: 21300308

Title: X-RAY SELECTED SYMBIOTIC BINARIES IN THE CHANDRA SOURCE CATALOG

PI Name: Robert Hynes

Binary evolution has broad astrophysical applications but models struggle with uncertainties. Observable populations constrain these uncertainties. Symbiotic stars (cool giants with compact companions) are binary evolution products, but also may be steps leading to double degenerate Type Ia supernova progenitors. Existing catalogs favor strong emission line objects. There is growing evidence for a hidden weak-line population that may be identified as X-ray selected giants. We will match the Chandra Source Catalog to bright IR counterparts in the Bulge. IR colors and magnitudes, proper-motions, and spectral energy distributions will separate cool giants from other objects. Joint NOAO/Gemini Time will initiate a spectroscopic classification program and confirm symbiotic identifications.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 21500527

Title: Quantifying Heavy Element Asymmetries in SNRs with Chandra

PI Name: Tyler Holland-Ashford

We propose an archival study to measure the asymmetries of elements within 15 Galactic supernova remnants (SNRs). 3D simulations of supernovae (SNe) have begun to generate testable predictions about the distribution of elements caused by asymmetric explosion mechanisms, namely that heavier elements should exhibit more asymmetry and should be most opposed to the direction of neutron star motion. We aim to test these predictions using Chandra X-ray images of 15 SNRs to determine the relative symmetry of different elements. We include both core-collapse (CC) and Type Ia SNRs in our sample to quantify the differences between the two populations.

Subject Category: SN, SNR AND ISOLATED NS

Proposal Number: 21500563

Title: X-ray content of Galactic Fermi LAT 4FGL sources

PI Name: Oleg Kargaltsev

With the release of 8-yr Fermi LAT catalog (4FGL) the number of unidentified GeV sources within 10 deg from the Galactic plane has nearly doubled (from 468 in 3FGL to 834 in 4FGL, which is 60% of all 4FGL sources within |b|<10 deg). This calls for intensifying multiwavelength classification efforts. Although Chandra has been observing LAT sources since the Fermi launch, the 4FGL positions of many sources have shifted outside the original error ellipses, and there are many new sources in 4FGL which have been only serendipitously covered by Chandra observations. We found about 90 unIDed 4FGL sources with Chandra ACIS observations which we propose to analyze using a multiwavelengths approach to classification. We expect to substantially increase the numbers of classified GeV sources.

Subject Category: NORMAL GALAXIES: X-RAY POPULATIONS

Proposal Number: 21620305

Title: Do LMXB populations vary among old early-type galaxies?

PI Name: Mark Peacock

We propose to determine the X-ray point source populations of 19 old early-type galaxies by utilizing 3 Ms of archival ACIS-S/I observations. Sources will be classified by matching to optical counterparts, producing a unique dataset of thousands of field and globular cluster LMXBs. Our target galaxies have high quality and homogeneous dynamical and stellar populations data from the Atlas3D survey. We will leverage these data to test for correlations between the LMXB populations and galaxy velocity dispersion, metallicity, and proposed IMF variations.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 21700098

Title: Improved constraints to the local black hole occupation fraction

PI Name: Elena Gallo

Cosmological volume simulations are fast approaching the resolution necessary to follow the assembly and evolution of galactic structure well below the knee of the galaxy mass function, where the black hole occupation fraction remains essentially unconstrained. In the low stellar mass regime (i.e. below ~1e10 solar masses), the BH occupation fraction determines the BH mass function, sets tidal disruption event rates, affects star formation quenching and may even depend on the BH seeding mechanisms at high-z. This archival program aims to push the observational constraints on the BH occupation to the highest accuracy attainable with existing data, including all suitable, on-axis observations of nearby galaxies within 30 Mpc, including late types.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 21700214

Title: HETG and NuSTAR: toward a Global picture for the X-ray reprocessor in AGN

PI Name: Tracey Turner

We propose to fit MYTORUS and BORUS models to five available simultaneous HETG/NuSTAR observations of AGN. This comprises the first systematic study to use the power of HETG to characterize the Fe K emission together with NuSTAR to constrain the global column density of circumnuclear material. This small sample will provide a first step in informing Unification Models and population synthesis models for the cosmic X-ray background.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 21700319

Title: Quantifying the Rate of Nearby Dual AGNs: Archival Sample

PI Name: Adi Foord

We propose to analyze a sample of 26 nearby (z<0.035) AGN in order to measure the dual AGN fraction in the small-separation regime, where current angular resolution limits have prevented systematic analyses. We will analyze the sample with BAYMAX, a tool we've developed that uses a Bayesian framework to quantitatively evaluate whether a given source in a Chandra observation is a single or dual point source for separations <0.5''. We plan to combine this sample with new observations of 55 AGN to constrain, for the first time, the nearby dual AGN fraction. The outcome of this study will be a measurement of the local dual AGN fraction, to within 2.8%, at smaller limiting separations (14-250 pc) than has ever been done before.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 21700372

Title: Does Excess Mid-Infrared Emission Reliably Signal an AGN?

PI Name: Cassandra Hatcher

We examine massive galaxies (M>10^9.5M) for the presence of active galactic nuclei (AGN) at redshifts z=0.5-3 in the COSMOS field. We use a sensitive IR selection technique combines near, mid, and far-IR colors to probe the full shape of the IR SED. Of galaxies probed so far, 50% show evidence of dust heating by supermassive black holes but lack X-ray detections. We propose to X-ray stack these sources to obtain hard and soft fluxes, securing our AGN detections and energetics. Preliminary results reveal IR AGN are highly obscured and unveil the success of joining Herschel and Spitzer colors for sensitive selection of IR AGN. We propose to continue this analysis on 1300 AGN candidates to gain better statistics and a complete census of AGN energetics at z=0.5-3.

Subject Category: ACTIVE GALAXIES AND QUASARS

Proposal Number: 21700442

Title: TRACKING THE GROWTH OF MASSIVE BLACK HOLES IN THE PROGENITORS OF DWARF GALAXIES

PI Name: Chien-Ting Chen

To constrain different formation paths of intermediate-mass (104-106 solar mass) black holes (IMBHs), we propose to measure the average BH accretion rates of the progenitors of present-day dwarf galaxies over the past 9 Gyr using deep Chandra observations in the CANDELS fields and in COSMOS, where a volume-limited sample of progenitors can be traced up to z 2. Due to the AGN downsizing phenomenon, our results can be used to derive most of the BH mass accumulated via accretion for the dwarf galaxies. This will determine whether the majority of dwarf galaxies can harbor IMBHs grown through typical accretion, or if the existence of IMBHs in the local universe requires massive BH seeds formed via the direct collapse of primordial gas clouds.

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 21800432

Title: Constraining the Origin of Optical Filaments in the Perseus Cluster with a Novel Technique

PI Name: Esra Bulbul

The central cluster galaxy in Perseus harbors one the best example of the network of filaments ubiquitous in cool core clusters. While those filaments have been heavily studied in the past, their formation and the mechanisms powering those filaments are still a matter of debate. The study of the filament's X-ray counterpart could probe its abundances and temperature providing better constraints on this multiphase gas, the heat dissipation processes and its origin. While previous studies have revealed a soft X-ray counterpart in some portions of the filaments, no study has been able to reveal the entire X-ray counterpart. Here we propose to revisit the deep archival Perseus observations with a novel 3D technique to reveal the entire X-ray counterpart and its spectral properties.

Subject Category: EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 21900326

Title: Exploring the Dawn of Supermassive Black Holes in Galaxy Cluster Lensing Fields

PI Name: Christine Jones

Supermassive black holes (SMBHs) in galaxy cores play critical roles in the formation and evolution of their hosts, but the origin and early growth of SMBHs remain a matter of intense investigation. We propose to use existing Chandra observations of the CLASH, Frontier Fields and RELICS clusters to probe the X-ray emission from growing SMBHs in the highest redshift galaxies (z = 5.5-10), by harnessing the power of lensing magnification by massive clusters. Our results will constrain models of the SMBH seed formation and test if SMBH growth follows that of their host galaxies at early epochs.

Subject Category: GALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 21910238

Title: Understanding the chemical enrichment and heating of the circumgalactic medium with observations of the Milky Way.

PI Name: Smita Mathur

We recently discovered the hottest component of the circumgalactic medium (CGM) of the Milky Way, with non-solar abundance ratios and alpha-enhancement of light metals. Excited by this discovery, we propose an archival program to determine whether the newly discovered properties along one sightline are general properties of the CGM. We will probe several sightlines across the sky with extremely high signal-to-noise grating spectra and also perform stacking analysis to obtain global properties in an average sense. Our results will provide insights on the heating and chemical enrichment of the CGM, its hydrodynamic properties, and its metal and mass content. Our program will yield guaranteed science results, providing inputs to models of galaxy formation, evolution and feedback.

Subject Category: GALACTIC DIFFUSE EMISSION AND SURVEYS

Proposal Number: 21910386

Title: Towards a complete classification of Galactic NuSTAR Sources with the Chandra Cool Attitude Target Program

PI Name: Francesca Fornasini

Hundreds of X-ray sources are being detected at hard X-ray energies for the first time through the NuSTAR serendipitous survey. To fully understand the nature of these sources, soft X-ray counterparts are needed to localize the sources with sufficient precision to identify optical/infrared counterparts. Precise localization is especially important for sources near the Galactic plane, where crowded fields make it challenging to identify unique counterparts. We propose to localize and study 5 NuSTAR sources located within 10 degrees of the Galactic plane with data obtained through the CAT program. We also request NOAO time to obtain deep near-IR images to search for infrared counterparts for these sources near the plane, where counterparts are often subject to high extinction.