Andrew M. Burkhardt
A5079811554- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Stellar, planetary, and galactic studies
- Space Satellite Systems and Control
- Atmospheric chemistry and aerosols
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- SAS software applications and methods
- Laser-induced spectroscopy and plasma
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Engineering and Test Systems
- Various Chemistry Research Topics
- Field-Flow Fractionation Techniques
- Assembly Line Balancing Optimization
- Nuclear Physics and Applications
- Flexible and Reconfigurable Manufacturing Systems
- Scientific Research and Discoveries
- Geochemistry and Geologic Mapping
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
Wellesley College
2022-2024
Worcester State University
2023-2024
Center for Astrophysics Harvard & Smithsonian
2019-2023
National Radio Astronomy Observatory
2015-2021
Smithsonian Astrophysical Observatory
2021
University of Virginia
2015-2021
Max Planck Institute for Extraterrestrial Physics
2021
Massachusetts Institute of Technology
2021
Benedictine College
2021
RTX (United States)
2017-2021
Polycyclic aromatic hydrocarbons and polycyclic nitrogen heterocycles are thought to be widespread throughout the Universe, because these classes of molecules probably responsible for unidentified infrared bands, a set emission features seen in numerous Galactic extragalactic sources. Despite their expected ubiquity, astronomical identification specific has proven elusive. We present discovery benzonitrile ($c$-C$_6$H$_5$CN), one simplest nitrogen-bearing molecules, interstellar medium....
Identifying PAHs in space Midinfrared spectroscopy has shown that polycyclic aromatic hydrocarbons (PAHs) are abundant many astronomical objects, but this technique cannot determine which specific PAH molecules present. Radio astronomy could provide individual identifications if the molecule is sufficiently and a large dipole moment, expected to produce numbers of very weak lines. McGuire et al. performed stacking matched filter analysis search for radio observations TMC-1, located within...
Polycyclic Aromatic Hydrocarbons (PAHs) have long been invoked in the study of interstellar and protostellar sources, but unambiguous identification any individual PAH has proven elusive until very recently. As a result, formation mechanisms for this important class molecules remain poorly constrained. Here we report first detection pure hydrocarbon PAH, indene (C$_9$H$_8$), as part GBT Observations TMC-1: Hunting Molecules (GOTHAM) survey. This provides new avenue chemical inquiry,...
We present laboratory rotational spectroscopy of five isomers cyanoindene (2-, 4-, 5-, 6-, and 7-cyanoindene) using a cavity Fourier-transform microwave spectrometer operating between 6-40 GHz. Based on these measurements, we report the detection 2-cyanoindene (1H-indene-2-carbonitrile; 2-C$_9$H$_7$CN) in GOTHAM line survey observations dark molecular cloud TMC-1 Green Bank Telescope at centimeter wavelengths. Using combination Markov Chain Monte Carlo (MCMC), spectral stacking, matched...
Context . JWST has taken the sharpest and most sensitive infrared (IR) spectral imaging observations ever of Orion Bar photodis-sociation region (PDR), which is part nearest massive star-forming Nebula, often considered to be ‘prototypical’ strongly illuminated PDR. Aims We investigate impact radiative feedback from stars on their natal cloud focus transition H II atomic PDR – crossing ionisation front (IF) –, subsequent molecular dissociation (DF). Given prevalence PDRs in interstellar...
Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent rings. Infrared emission bands show that PAHs abundant in space, but only a few specific have been detected the interstellar medium. We 1-cyanopyrene, cyano-substituted derivative of related four-ring PAH pyrene, radio observations dense cloud TMC-1, using Green Bank Telescope. The measured column density 1-cyanopyrene is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"...
Abstract We present an overview of the GBT Observations TMC-1: Hunting Aromatic Molecules Large Program on Green Bank Telescope. This and a related program were launched to explore depth breadth aromatic chemistry in interstellar medium at earliest stages star formation, following our earlier detection benzonitrile ( c -C 6 H 5 CN) TMC-1. In this work, details observations, use archival data, data reduction strategies are provided. Using these propargyl cyanide (HCCCH 2 is described, as well...
Abstract Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy throughout universe, from era vigorous star formation at redshifts 1–3 to present day. The dominant can be probed by observations Photo-Dissociation Regions (PDRs) where far-ultraviolet photons massive create warm regions gas dust neutral atomic gas. PDR emission provides a unique...
We have conducted an extensive search for nitrogen-, oxygen-, and sulfur-bearing heterocycles toward Taurus Molecular Cloud 1 (TMC-1) using the deep, broadband centimeter-wavelength spectral line survey of region from GOTHAM large project on Green Bank Telescope. Despite their ubiquity in terrestrial chemistry, confirmed presence a number cyclic polycyclic hydrocarbon species source, we find no evidence any heterocyclic species. Here, report derived upper limits column densities these...
Abstract Using data from the Green Bank Telescope (GBT) Observations of TMC-1: Hunting for Aromatic Molecules (GOTHAM) survey, we report first astronomical detection C 10 H − anion. The observations also provided necessary to refine spectroscopic parameters . From velocity stacked and matched filter response, is detected at >9 σ confidence level a column density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>4.04</mml:mn>...
Polycyclic aromatic hydrocarbons (PAHs) are among the most widespread compounds in universe, accounting for up to ~25% of all interstellar carbon. Since unsubstituted PAHs do not possess permanent electric dipole moments, they invisible radio astronomy. Constraining their abundances relies on detection polar chemical proxies, such as nitriles. Here we report 2-cyanopyrene and 4-cyanopyrene, isomers recently detected 1-cyanopyrene. We find that these present an abundance ratio ~2:1:2, which...
Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict this FUV radiation produces photodissociation regions (PDRs) on the surfaces protoplanetary disks around affects planet formation within disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations a FUV-irradiated disk Orion Nebula. Emission lines detected from PDR; modeling their kinematics excitation...
A sensitive broadband molecular line survey of the Sagittarius B2(N) star-forming region has been obtained with Heterodyne Instrument for Far-Infrared (HIFI) instrument on Herschel Space Observatory, offering first high spectral resolution look at this well-studied source in a wavelength largely inaccessible from ground (625–157 μm). From roughly 8000 features survey, total 72 isotopologues arising 44 different molecules have identified, ranging light hydrides to complex organics, and...
Abstract We report the detection of interstellar methoxymethanol (CH 3 OCH 2 OH) in Atacama Large Millimeter/submillimeter Array (ALMA) Bands 6 and 7 toward MM1 core high-mass star-forming region NGC 6334I at ∼0.″1–1″ spatial resolution. A column density 4(2) × 10 18 cm −2 T ex = 200 K is derived MM1, ∼34 times less abundant than methanol OH), significantly higher predicted by astrochemical models. Probable formation destruction pathways are discussed, primarily through reaction CH OH...
Abstract Using radio observations with the Green Bank Telescope, evidence has now been found for a second five-membered ring in dense cloud Taurus Molecular Cloud-1 (TMC-1). Based on additional of an ongoing, large-scale, high-sensitivity spectral line survey (GOTHAM) at centimeter wavelengths toward this source, we have used combination stacking, Markov Chain Monte Carlo (MCMC), and matched filtering techniques to detect 2-cyanocyclopentadiene, low-lying isomer 1-cyanocyclopentadiene, which...
(Abridged) Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs found at 3.3, 6.2, 7.7, 8.6, and 11.2 $\mu$m. sensitive, highest-resolution spectral imaging data ever taken the prototypical PDR, Orion Bar, have been captured JWST. We provide an inventory in along with mid-IR template spectra from five distinct Bar: molecular atomic HII region. use JWST NIRSpec IFU MIRI MRS Bar...
Context . The James Webb Space Telescope (JWST) has captured the most detailed and sharpest infrared (IR) images ever taken of inner region Orion Nebula, nearest massive star formation region, a prototypical highly irradiated dense photo-dissociation (PDR). Aims We investigate fundamental interaction far-ultraviolet (FUV) photons with molecular clouds. transitions across ionization front (IF), dissociation (DF), cloud are studied at high-angular resolution. These relevant to understanding...
Abstract We report the detection of lowest-energy conformer E -1-cyano-1,3-butadiene ( -1- <?CDATA ${{\rm{C}}}_{4}{{\rm{H}}}_{5}\mathrm{CN}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">C</mml:mi> </mml:mrow> <mml:mn>4</mml:mn> </mml:msub> mathvariant="normal">H</mml:mi> <mml:mn>5</mml:mn> <mml:mi>CN</mml:mi> </mml:math> ), a linear isomer pyridine, using fourth data reduction GBT Observations TMC-1: Hunting...
Context . Mid-infrared observations of photodissociation regions (PDRs) are dominated by strong emission features called aromatic infrared bands (AIBs). The most prominent AIBs found at 3.3, 6.2, 7.7, 8.6, and 11.2 µm. sensitive, highest-resolution spectral imaging data ever taken the prototypical PDR, Orion Bar, have been captured JWST. These high-quality allow for an unprecedentedly detailed view AIBs. Aims We provide inventory in along with mid-IR template spectra from five distinct Bar:...
Bell et al. reported the first detection of cyanopolyyne HC11N towards cold dark cloud TMC-1; no subsequent detections have been any source. Additional observations cyanopolyynes and other carbon-chain molecules TMC-1 shown a log-linear trend between molecule size column density, in an effort to further explore underlying chemical processes driving this trend, we analysed Green Bank Telescope HC9N TMC-1. Although find density consistent with previous values, is not detected derive upper...
We report an astronomical detection of HC$_4$NC for the first time in interstellar medium with Green Bank Telescope toward TMC-1 molecular cloud a minimum significance $10.5 \sigma$. The total column density and excitation temperature are determined to be $3.29^{+8.60}_{-1.20}\times 10^{11}$ cm$^{-2}$ $6.7^{+0.3}_{-0.3}$ K, respectively, using MCMC analysis. In addition HC$_4$NC, HCCNC is distinctly detected whereas no clear HC$_6$NC made. propose that dissociative recombination protonated...