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186 results on '"Remijan, Anthony J."'

153. Spatial Distributions and Interstellar Reaction Processes

Author

Neill, Justin L., primary, Steber, Amanda L., additional, Muckle, Matt T., additional, Zaleski, Daniel P., additional, Lattanzi, Valerio, additional, Spezzano, Silvia, additional, McCarthy, Michael C., additional, Remijan, Anthony J., additional, Friedel, Douglas N., additional, Widicus Weaver, Susanna L., additional, and Pate, Brooks H., additional

Published
2011
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156. SIMULTANEOUS OBSERVATIONS OF COMET C/2002 T7 (LINEAR) WITH THE BERKELEY-ILLINOIS-MARYLAND ASSOCIATION AND OWENS VALLEY RADIO OBSERVATORY INTERFEROMETERS: HCN AND CH3OH

Author

Hogerheijde, Michiel R., primary, Qi, Chunhua, additional, de Pater, Imke, additional, Blake, Geoffrey A., additional, Friedel, D. N., additional, Forster, J. R., additional, Palmer, Patrick, additional, Remijan, Anthony J., additional, Snyder, L. E., additional, and Wright, M. C. H., additional

Published
2009
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157. The Distribution, Excitation, and Formation of Cometary Molecules: Methanol, Methyl Cyanide, and Ethylene Glycol

Author

Remijan, Anthony J., primary, Milam, Stefanie N., additional, Womack, Maria, additional, Apponi, A. J., additional, Ziurys, L. M., additional, Wyckoff, Susan, additional, A’Hearn, M. F., additional, de Pater, Imke, additional, Forster, J. R., additional, Friedel, D. N., additional, Palmer, Patrick, additional, Snyder, L. E., additional, Veal, J. M., additional, Woodney, L. M., additional, and Wright, M. C. H., additional

Published
2008
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162. Formaldehyde in Comets C/1995 O1 (Hale‐Bopp), C/2002 T7 (LINEAR), and C/2001 Q4 (NEAT): Investigating the Cometary Origin of H2CO

Author

Milam, Stefanie N., primary, Remijan, Anthony J., additional, Womack, Maria, additional, Abrell, Leif, additional, Ziurys, L. M., additional, Wyckoff, Susan, additional, Apponi, A. J., additional, Friedel, D. N., additional, Snyder, L. E., additional, Veal, J. M., additional, Palmer, Patrick, additional, Woodney, L. M., additional, A’Hearn, Michael F., additional, Forster, J. R., additional, Wright, M. C. H., additional, de Pater, I., additional, Choi, S., additional, and Gesmundo, M., additional

Published
2006
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164. A BIMA Array Survey of Molecules in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4)

Author

Remijan, Anthony J., primary, Friedel, D. N., additional, de Pater, Imke, additional, Hogerheijde, M. R., additional, Snyder, L. E., additional, A’Hearn, M. F., additional, Blake, Geoffrey A., additional, Dickel, H. R., additional, Forster, J. R., additional, Kraybill, C., additional, Looney, L. W., additional, Palmer, Patrick, additional, and Wright, M. C. H., additional

Published
2006
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173. BIMA Array Detections of HCN in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4)

Author

Friedel, D. N., primary, Remijan, Anthony J., additional, Snyder, L. E., additional, A’Hearn, M. F., additional, Blake, Geoffrey A., additional, de Pater, Imke, additional, Dickel, H. R., additional, Forster, J. R., additional, Hogerheijde, M. R., additional, Kraybill, C., additional, Looney, L. W., additional, Palmer, Patrick, additional, and Wright, M. C. H., additional

Published
2005
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175. A SEARCH FOR l-C3H+ AND l-C3H IN Sgr B2(N), Sgr B2(OH), AND THE DARK CLOUD TMC-1.

Author

MCGUIRE, BRETT A., CARROLL, P. BRANDON, LOOMIS, RYAN A., BLAKE, GEOFFREY A., HOLLIS, JAN M., LOVAS, FRANK J., JEWELL, PHILIP R., and REMIJAN, ANTHONY J.

Subjects
INTERSTELLAR medium, ASTRONOMICAL spectroscopy, BLACK holes, ASTROCHEMISTRY, SURVEYS, TEMPERATURE -- Mathematical models
Abstract

Pety et al. recently reported the detection of several transitions of an unknown carrier in the Horsehead PDR and attribute them to l-C3H+. Here, we have tested the predictive power of their fit by searching for, and identifying, the previously unobserved J = 1-0 and J = 2-1 transitions of the unknown carrier (B11244) toward Sgr B2(N) in data from the publicly available PRIMOS project. Also presented here are observations of the J = 6-5 and J = 7-6 transitions toward Sgr B2(N) and Sgr B2(OH) using the Barry E. Turner Legacy Survey and results from the Kaifu et al. survey of TMC-1. We calculate an excitation temperature and column density of B11244 of ~10 K and ~1013 cm-2 in Sgr B2(N) and ~79 K with an upper limit of ⩽1.5 × 1013 cm-2 in Sgr B2(OH) and find trace evidence for the cation's presence in TMC-1. Finally, we present spectra of the neutral species in both Sgr B2(N) and TMC-1, and comment on the robustness of the assignment of the detected signals to l-C3H+. [ABSTRACT FROM AUTHOR]

Published
2013
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180. Cyclopropenone (c-H2C3O): A New Interstellar Ring Molecule

Author

Remijan, Anthony J.

Abstract

The three-carbon keto ring cyclopropenone (c-H2C 3O) has been detected largely in absorption with the 100 m Green Bank Telescope (GBT) toward the star-forming region Sagittarius B2(N) by means of a number of rotational transitions between energy levels that have energies less than 10 K. Previous negative results from searches for interstellar c-H2C3O by other investigators attempting to detect rotational transitions that have energy levels ~10 K or greater indicate no significant hot core component. Thus, we conclude that only the low-energy levels of c-H2C3O are populated because the molecule state temperature is low, suggesting that c-H2C3O resides in a star-forming core halo region that has a widespread arcminute spatial scale. Toward Sagittarius B2(N), the GBT was also used to observe the previously reported, spatially ubiquitous, three-carbon ring cyclopropenylidene (c-C3H2 ), which has a divalent carbon that makes it highly reactive in the laboratory. The presence of both c-C3H2 and c-H2C3O toward Sagittarius B2(N) suggests that gas-phase oxygen addition may account for the synthesis of c-H 2C3O from c-C3H2. We also searched for but did not detect the three-carbon sugar glyceraldehyde (CH2OHCHOHCHO).

Published
2006

181. BIMA Array Detections of HCN in Comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4)

Author

Remijan, Anthony J., Blake, Geoffrey A., Pater, Imke de, and Palmer, Patrick

Abstract

We present interferometric detections of HCN in comets LINEAR (C/2002 T7) and NEAT (C/2001 Q4) with the Berkeley-Illinois-Maryland Association (BIMA) array. With a 25.''4 x 20.''3 synthesized beam around comet LINEAR and using a variable temperature and outflow velocity (VTOV) model, we found an HCN column density of [?]NT[?] = (6.4 +- 2.1) x 1012 cm-2 and a production rate of Q(HCN) = (6.5 +- 2.2) x 1026 s-1, giving a production rate ratio of HCN relative to H2O of ~(3.3 +- 1.1) x 10-3 and relative to CN of ~4.6 +- 1.5. With a 21.''3 x 17.''5 synthesized beam around comet NEAT and using a VTOV model, we found an HCN column density of img1.gif = (8.5 +- 4.5) x 1011 cm-2 and a production rate of Q(HCN) = (8.9 +- 4.7) x 1025 s-1, giving a production rate ratio of HCN relative to H2O of ~(7.4 +- 3.9) x 10-4 and relative to CN of ~0.3 +- 0.2. For both comets, the production rates relative to H2O are similar to those found in previous comet observations. For comet LINEAR, the production rate relative to CN is consistent with HCN being the primary parent species of CN, while for comet NEAT it is too low for this to be the case.

Published
2005

184. Detection of the aromatic molecule benzonitrile (c-C6H5CN) in the interstellar medium.

Author

McGuire, Brett A., Burkhardt, Andrew M., Kalenskii, Sergei, Shingledecker, Christopher N., Remijan, Anthony J., Herbst, Eric, and McCarthy, Michael C.

Subjects
*BENZONITRILE, *MOLECULES, *MOLECULAR clouds, *POLYCYCLIC aromatic hydrocarbons, *GALAXIES
Abstract

Polycyclic aromatic hydrocarbons and polycyclic aromatic nitrogen heterocycles are thought to be widespread throughout the universe, because these classes of molecules are probably responsible for the unidentified infrared bands, a set of emission features seen in numerous Galactic and extragalactic sources. Despite their expected ubiquity, astronomical identification of specific aromatic molecules has proven elusive. We present the discovery of benzonitrile (c-C6H5CN), one of the simplest nitrogen-bearing aromatic molecules, in the interstellar medium. We observed hyperfine-resolved transitions of benzonitrile in emission from the molecular cloud TMC-1. Simple aromatic molecules such as benzonitrile may be precursors for polycyclic aromatic hydrocarbon formation, providing a chemical link to the carriers of the unidentified infrared bands. [ABSTRACT FROM AUTHOR]

Published
2018
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185. Discovery of the interstellar chiral molecule propylene oxide (CH3CHCH2O).

Author

McGuire, Brett A., Carroll, P. Brandon, Loomis, Ryan A., Finneran, Ian A., Jewell, Philip R., Remijan, Anthony J., and Blake, Geoffrey A.

Subjects
*CHIRALITY, *PROPYLENE oxide, *INTERSTELLAR molecules, *GALACTIC center, *ABSORPTION spectra, *PLANETARY systems, *GAS phase reactions, *SOLAR system, EVOLUTION
Abstract

Life on Earth relies on chiral molecules--that is, species not superimposable on their mirror images. This manifests itself in the selection of a singlemolecular handedness, or homochirality, across the biosphere. We present the astronomical detection of a chiral molecule, propylene oxide (CH3CHCH2O), in absorption toward the Galactic center. Propylene oxide is detected in the gas phase in a cold, extended molecular shell around the embedded, massive protostellar clusters in the Sagittarius B2 star-forming region. This material is representative of the earliest stage of solar system evolution in which a chiral molecule has been found. [ABSTRACT FROM AUTHOR]

Published
2016
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186. Detection of interstellar 1-cyanopyrene: A four-ring polycyclic aromatic hydrocarbon.

Author

Wenzel G, Cooke IR, Changala PB, Bergin EA, Zhang S, Burkhardt AM, Byrne AN, Charnley SB, Cordiner MA, Duffy M, Fried ZTP, Gupta H, Holdren MS, Lipnicky A, Loomis RA, Shay HT, Shingledecker CN, Siebert MA, Stewart DA, Willis RHJ, Xue C, Remijan AJ, Wendlandt AE, McCarthy MC, and McGuire BA

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent aromatic rings. Infrared emission bands show that PAHs are abundant in space, but only a few specific PAHs have been detected in the interstellar medium. We detected 1-cyanopyrene, a cyano-substituted derivative of the related four-ring PAH pyrene, in radio observations of the dense cloud TMC-1, using the Green Bank Telescope. The measured column density of 1-cyanopyrene is [Formula: see text] cm -2 , from which we estimate that pyrene contains up to 0.1% of the carbon in TMC-1. This abundance indicates that interstellar PAH chemistry favors the production of pyrene. We suggest that some of the carbon supplied to young planetary systems is carried by PAHs that originate in cold molecular clouds.

Published
2024
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