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Astrophysics and Astronomy

Min S. Yun

Articles 1 - 30 of 33

Full-Text Articles in Physical Sciences and Mathematics

H I Asymmetries In The Isolated Galaxy Cig 292, Antonio Portas, Tom C. Scott, Elias Brinks, Albert Bosma, Lourdes Verdes-Montenegro, Volker Heesen, Daniel Espada, Simon Verley, Jack Sulentic, Chandreyee Sengupta, E Athanassoula, Min S. Yun Aug 2011

H I Asymmetries In The Isolated Galaxy Cig 292, Antonio Portas, Tom C. Scott, Elias Brinks, Albert Bosma, Lourdes Verdes-Montenegro, Volker Heesen, Daniel Espada, Simon Verley, Jack Sulentic, Chandreyee Sengupta, E Athanassoula, Min S. Yun

Min S. Yun

We present Expanded Very Large Array (EVLA) D-array observations of the 21 cm line of neutral hydrogen (H I) of CIG 292, an isolated SA(s)b galaxy at a distance of ~24.3 Mpc. From previous H I single dish observations the galaxy was known to have a mildly asymmetric H I profile (A flux = 1.23 ± 0.3). Our EVLA observations show there is ~12% more H I projected south of the optical center (approaching velocities) than in the north (receding velocities), despite the H I extending ~16% further to the north than the south. The H I projected within the …

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Neutral Hydrogen Clouds In The M81/M82 Group, Katie M. Chynoweth, Glen I. Langston, Min S. Yun, Felix J. Lockman, K H R Rubin, Sarah A. Scoles Apr 2008

Neutral Hydrogen Clouds In The M81/M82 Group, Katie M. Chynoweth, Glen I. Langston, Min S. Yun, Felix J. Lockman, K H R Rubin, Sarah A. Scoles

Min S. Yun

We have observed a 3° × 3° area centered on the M81/M82 group of galaxies using the Robert C. Byrd Green Bank Telescope in a search for analogs to the high-velocity clouds of neutral hydrogen found around our Galaxy. The velocity range from –605 to –85 km s–1 and from 25 to 1970 km s–1 was searched for H I clouds. Over the inner 2° × 2° the 7σ detection threshold was 9.6 × 105 M sun. We detect five previously unknown H I clouds associated with the group, as well as numerous associated filamentary H I structures, all lying …

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Dust Emissions From High-Redshift Qsos, C L. Carilli, K M. Bertoldi, K M. Menten, M P. Rupen, E Kreysa, Xiaohui Fan, Michael A. Strauss, Donald P. Schneider, A Bertarini, Min S. Yun, R Zylka Apr 2000

Dust Emissions From High-Redshift Qsos, C L. Carilli, K M. Bertoldi, K M. Menten, M P. Rupen, E Kreysa, Xiaohui Fan, Michael A. Strauss, Donald P. Schneider, A Bertarini, Min S. Yun, R Zylka

Min S. Yun

We present detections of emission at 250 GHz (1.2 mm) from two high-redshift QSOs from the Sloan Digital Sky Survey sample using the bolometer array at the IRAM 30 m telescope. The sources are SDSSp 015048.831004126.2 at z = 3.7 and SDSSp J033829.311002156.3 at z = 5.0; the latter is the third highest redshift QSO known and the highest redshift millimeter-emitting source yet identified. We also present deep radio continuum imaging of these two sources at 1.4 GHz using the Very Large Array. The combination of centimeter and millimeter observations indicate that the 250 GHz emission is most likely thermal …

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Neutral Hydrogen Distribution In Merging Galaxies: Differences Between Stellar And Gaseous Tidal Morphologies, J E. Hibbard, W D. Vacca, Min S. Yun Mar 2000

Neutral Hydrogen Distribution In Merging Galaxies: Differences Between Stellar And Gaseous Tidal Morphologies, J E. Hibbard, W D. Vacca, Min S. Yun

Min S. Yun

As part of several H I synthesis-mapping studies of merging galaxies, we have mapped the tidal gas in the three disk-disk merger systems Arp 157 (NGC 520), Arp 220, and Arp 299 (NGC 3690). These systems differ from the majority of the mergers mapped in H I in that their stellar and gaseous tidal features do not coincide. In particular, they exhibit large stellar tidal features with little if any accompanying neutral gas and large gas-rich tidal features with little if any accompanying starlight. On smaller scales, there are striking anticorrelations in which the gaseous and stellar tidal features appear …

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The Scatter In The Relationship Between Redshift And The Radio-To-Submm Spectral Index, C L. Carilli, Min S. Yun Feb 2000

The Scatter In The Relationship Between Redshift And The Radio-To-Submm Spectral Index, C L. Carilli, Min S. Yun

Min S. Yun

We derive the scatter in the relationship between redshift and the radio-to-submillimeter spectral index, a135.40, using the observed spectral energy distributions of 17 low-redshift star-forming galaxies. A mean galaxy model is derived, along with the rms scatter in a13.540. The scatter is roughly constant with redshift. Constant rms scatter, combined with the Ñattening of the mean a13.540-z relationship with increasing redshift, leads to increasing uncertainty for redshift estimates at high redshifts. Normalizing by the dust temperature in the manner proposed by Blain decreases the scatter in a13.540 for most of the sample, but does not remove outliers, and free-free absorption …

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Sensitive Radio Observations Of High-Redshift Dusty Qsos, Min S. Yun, C L. Carilli, R Kawabe, Y Tutui, K Kohno, K Ohta Jan 2000

Sensitive Radio Observations Of High-Redshift Dusty Qsos, Min S. Yun, C L. Carilli, R Kawabe, Y Tutui, K Kohno, K Ohta

Min S. Yun

We present sensitive radio continuum imaging at 1.4 and 4.9 GHz of seven high-redshift QSOs selected for having a 240 GHz continuum detection, which is thought to be thermal dust emission. We detect radio continuum emission from four of the sources: BRI 0952-0115, BR 1202-0725, LBQS 1230+1627B, and BRI 1335-0417. The radio source in BR 1202-0725 is resolved into two components, coincident with the double millimeter and CO sources. We compare the results at 1.4 and 240 GHz to empirical and semianalytic spectral models based on star-forming galaxies at low redshift. The radio-to-submillimeter spectral energy distribution (SED) for BR 1202-0725, …

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Tracing Interactions In Hickson Compact Groups Through The Hi, L Verdes-Montenegro, Min S. Yun, B A. Williams, W K. Huchtmeier, A Del Olmo, J Perea Sep 1999

Tracing Interactions In Hickson Compact Groups Through The Hi, L Verdes-Montenegro, Min S. Yun, B A. Williams, W K. Huchtmeier, A Del Olmo, J Perea

Min S. Yun

We present a global study of HI spectral line mapping for 16 Hickson Compact Groups (HCGs) combining new and unpublished VLA data, plus the analysis of the HI content of individual galaxies. Sixty percent of the groups show morphological and kinematical signs of perturbations (from multiple tidal features to concentration of the HI in a single enveloping cloud) and sixty five of the resolved galaxies are found to be HI deficient with respect to a sample of isolated galaxies. In total, 77% of the groups suffer interactions among all its members which provides strong evidence of their reality. We find …

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Luminosity Profiles Of Merger Remnants, J E. Hibbard, Min S. Yun Aug 1999

Luminosity Profiles Of Merger Remnants, J E. Hibbard, Min S. Yun

Min S. Yun

Using published luminosity and molecular gas profiles of the late-stage mergers NGC 3921, NGC 7252, and Arp 220, we examine the expected luminosity profiles of the evolved merger remnants, especially in light of the massive CO complexes that are observed in their nuclei. For NGC 3921 and NGC 7252, we predict that the resulting luminosity profiles will be characterized by an r1/4 law. In view of previous optical work on these systems, it seems likely that they will evolve into normal elliptical galaxies as regards their optical properties. Due to a much higher central molecular gas column density, Arp 220 …

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Detection Of Co (2-1) And Radio Continuum Emission From The Z = 4.4 Qso Bri 1335–0417, C L. Carilli, Karl M. Menten, Min S. Yun Aug 1999

Detection Of Co (2-1) And Radio Continuum Emission From The Z = 4.4 Qso Bri 1335–0417, C L. Carilli, Karl M. Menten, Min S. Yun

Min S. Yun

We have detected redshifted CO (2-1) emission at 43 GHz and radio continuum emission at 1.47 and 4.86 GHz from the z = 4.4 QSO BRI 1335-0417 using the Very Large Array. The CO data imply optically thick emission from warm (>30 K) molecular gas with a total mass, M(H2), of (1.5 ± 0.3) × 1011 Msun, using the standard Galactic gas mass-to-CO luminosity conversion factor. We set an upper limit to the CO source size of 1farcs1 and a lower limit of 0farcs23(Tex/50 K)-1/2, where Tex is the gas excitation temperature. We derive an upper limit to the …

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Molecular Gas In The Z = 2.565 Submillimeter Galaxy Smm J14011+0252, D T. Frayer, R J. Ivison, N Z. Scoville, A S. Evans, Min S. Yun, Ian Smail, A J. Barger, A W. Blain, J P. Kneib Mar 1999

Molecular Gas In The Z = 2.565 Submillimeter Galaxy Smm J14011+0252, D T. Frayer, R J. Ivison, N Z. Scoville, A S. Evans, Min S. Yun, Ian Smail, A J. Barger, A W. Blain, J P. Kneib

Min S. Yun

We report the detection of CO (3 r 2) emission from the submillimeter-selected luminous galaxy SMM J1401110252. The optical counterpart of the submillimeter source has been identified as a merger system with spectral characteristics consistent with a starburst at z 5 2.565. The CO emission confirms the optical identification of the submillimeter source and implies a molecular gas mass of M,5#1010 h22 , after correcting 75 for a lensing amplification factor of 2.75. The large molecular gas mass and the radio emission are consistent with the starburst interpretation of the source. These results are similar to those found for SMM …

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The Radio-To-Submillimeter Spectral Index As A Redshift Indicator, C L. Carilli, Min S. Yun Mar 1999

The Radio-To-Submillimeter Spectral Index As A Redshift Indicator, C L. Carilli, Min S. Yun

Min S. Yun

We present models of the 1.4 to 350 GHz spectral index 350 for starburst galaxies as a function of redshift. a1.4 The models include a semianalytic formulation, based on the well-quantified radio–to–far-infrared correlation for low-redshift star-forming galaxies, and an empirical formulation, based on the observed spectrum of the starburst galaxies M82 and Arp 220. We compare the models to the observed values of 350 for starburst galaxies at low a1.4 and high redshift. We find reasonable agreement between the models and the observations and, in particular, that an observed spectral index of 350 indicates that the target source is likely …

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Co Distribution And Kinematics Along The Bar In The Strongly Barred Spiral Ngc 7479, S Laine, J D P Kenny, Min S. Yun, S T. Gottesman Feb 1999

Co Distribution And Kinematics Along The Bar In The Strongly Barred Spiral Ngc 7479, S Laine, J D P Kenny, Min S. Yun, S T. Gottesman

Min S. Yun

We report on the 2farcs5 (400 pc) resolution CO (J=1→0) observations covering the whole length of the bar in the strongly barred late-type spiral galaxy NGC 7479. CO emission is detected only along a dust lane that traverses the whole length of the bar, including the nucleus. The emission is strongest in the nucleus. The distribution of emission is clumpy along the bar outside the nucleus and consists of gas complexes that are unlikely to be gravitationally bound. The CO kinematics within the bar consist of two separate components. A kinematically distinct circumnuclear disk, <500 pc in diameter, is undergoing predominantly circular motion with a maximum rotational velocity of 245 km s-1 at a radius of 1'' (160 pc). The CO-emitting gas in the bar outside the circumnuclear disk has substantial noncircular motions that are consistent with a large radial velocity component, directed inward. The CO emission has a large velocity gradient across the bar dust lane, ranging from 0.5 to 1.9 km s-1 pc-1 after correcting for inclination, and the projected velocity change across the dust lane is as high as 200 km s-1. This sharp velocity gradient is consistent with a shock front at the location of the bar dust lane. A comparison of Hα and CO kinematics across the dust lane shows that, although the Hα emission is often observed both upstream and downstream from the dust lane, the CO emission is observed only where the velocity gradient is large. We also compare the observations with hydrodynamic models and discuss star formation along the bar.

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Submillimeter Imaging Of The Luminous Infrared Galaxy Pair Vv 114, D T. Frayer, R J. Ivison, I Smail, L Armus, Min S. Yun Jan 1999

Submillimeter Imaging Of The Luminous Infrared Galaxy Pair Vv 114, D T. Frayer, R J. Ivison, I Smail, L Armus, Min S. Yun

Min S. Yun

We report on 450 and 850 μm observations of the interacting galaxy pair VV 114 E+W (IC 1623), taken with the SCUBA camera on the James Clerk Maxwell Telescope, and near-infrared observations taken with the UKIRT Fast-Track Imager on the UK Infrared Telescope. The system VV 114 is in an early stage of a gas-rich merger. We detect submillimeter emission extended over 30'' (12 kpc) and find a good correlation between the spatial distribution of the submillimeter and CO emission. Both the CO and submillimeter emission peak near the reddest region of VV 114 E and extend toward VV 114 …

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Counterrotating Nuclear Disks In Arp 220, K Sakamoto, N Z. Scoville, Min S. Yun, M Crosas, R Genzel, L J. Tacconi Jan 1999

Counterrotating Nuclear Disks In Arp 220, K Sakamoto, N Z. Scoville, Min S. Yun, M Crosas, R Genzel, L J. Tacconi

Min S. Yun

The ultraluminous infrared galaxy Arp 220 has been observed at 0farcs5 resolution in CO (2-1) and 1 mm continuum using the newly expanded Owens Valley Millimeter Array. The CO and continuum peaks at the double nuclei and the surrounding molecular gas disk are clearly resolved. We find steep velocity gradients across each nucleus (ΔV~500 km s-1 within r=0farcs3) whose directions are not aligned with each other and with that of the outer gas disk. We conclude that the double nuclei have their own gas disks (r~100 pc), are counterrotating with respect to each other, and are embedded in the outer …

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Co (J = 4 → 3) And 650 Micron Continuum Observations Of The Z = 0.93 Hyperluminous Infrared Galaxy Fsc 15307+3252, Min S. Yun, N Z. Scoville Nov 1998

Co (J = 4 → 3) And 650 Micron Continuum Observations Of The Z = 0.93 Hyperluminous Infrared Galaxy Fsc 15307+3252, Min S. Yun, N Z. Scoville

Min S. Yun

We report the results of our CO J = 4 → 3 line and rest-frame 650 μm continuum observations of the z = 0.93 hyperluminous infrared galaxy FSC 15307+3252 using the Owens Valley Millimeter Array. No line or continuum emission was detected, but the derived limits provide a useful constraint on the temperature, emissivity, and mass of the cold dust associated with FSC 15307+3252 and its molecular gas content. The 3 σ upper limit on the velocity-integrated CO (4-3) line flux is 1.6 Jy km s-1 (for ΔV = 300 km s-1). This corresponds to a surprisingly small total molecular …

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Molecular Gas In The Z = 2.8 Submillimeter Galaxy Smm 02399-0136, D T. Frayer, R J. Ivison, N Z. Scoville, Min S. Yun, A S. Evans, Ian Smail, A W. Blain, J P. Kneib Oct 1998

Molecular Gas In The Z = 2.8 Submillimeter Galaxy Smm 02399-0136, D T. Frayer, R J. Ivison, N Z. Scoville, Min S. Yun, A S. Evans, Ian Smail, A W. Blain, J P. Kneib

Min S. Yun

We report the detection of CO (3→2) emission from the submillimeter-selected hyperluminous galaxy SMM 02399-0136. This galaxy is the brightest source detected in the recent Submillimeter Common-User Bolometer Array surveys of the submillimeter sky. The optical counterpart of the submillimeter source has been identified as a narrow-line active galactic nucleus/starburst galaxy at z=2.8. The CO emission is unresolved, θlesssim5'', and is coincident in redshift and position with the optical counterpart. The molecular gas mass derived from the CO observations is 8×1010 h−275 M_{{\odot}}, after correcting for a lensing amplification factor of 2.5. The large CO luminosity suggests that a significant …

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Redshifted Neutral Hydrogen 21 Centimeter Absorption Toward Red Quasars, C L. Carilli, Karl M. Menten, Mark J. Reid, M P. Rupen, Min S. Yun Feb 1998

Redshifted Neutral Hydrogen 21 Centimeter Absorption Toward Red Quasars, C L. Carilli, Karl M. Menten, Mark J. Reid, M P. Rupen, Min S. Yun

Min S. Yun

We have searched for redshifted neutral hydrogen 21 cm absorption toward sources from the Stickel et al. "red quasar" subsample. The red quasar subsample is taken from the 1 Jy sample of flat-spectrum radio sources and is comprised of the 15 sources that are undetected on the POSS. Five of these red quasars have been searched for redshifted H I 21 cm absorption to optical depth levels of a few percent, and four show strong absorption, with neutral hydrogen column densities between 4 and 80 × 1018 × (Ts/f) cm-2. This 80% success rate for the red quasars compares to …

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Molecular Gas In The Inner 100 Parces Of M51, N Z. Scoville, Min S. Yun, L Armus, H Ford Jan 1998

Molecular Gas In The Inner 100 Parces Of M51, N Z. Scoville, Min S. Yun, L Armus, H Ford

Min S. Yun

We report imaging of CO (2-1) emission in the nucleus of M51 at 1'' (47 pc) resolution. Molecular gas is found closely associated with the nuclear radio jet and the X-shaped dust absorption feature seen in the Hubble Space Telescope images. The CO emission lies along the side of the nuclear radio continuum "jet." The strongest molecular emission is not symmetric in either position or velocity with respect to the nucleus—the dominant feature is at redshifted velocities and peaks 1'' to the west of the radio/optical nucleus. The CO (2-1) emission has an integrated flux implying a molecular gas mass …

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Nature Of 60Μm Emission In 3c 47, 3c 207 And 3c 334, Ilse M. Van Bemmel, Peter D. Barthel, Min S. Yun Jan 1998

Nature Of 60Μm Emission In 3c 47, 3c 207 And 3c 334, Ilse M. Van Bemmel, Peter D. Barthel, Min S. Yun

Min S. Yun

We try to explain the unusually high far-infrared emission seen by IRAS in the double-lobed radio-loud quasars 3C 47, 3C 207 and 3C 334. High resolution cm–mm observations were carried out to determine their radio core spectra, which are subsequently extrapolated to the far-infrared in order to determine the strength of the synchrotron far-infrared emission. The extrapolated flux densities being considerably lower than the observed values, a significant nonthermal far-infrared component is unlikely in the case of 3C 47 and 3C 334. However, this component could be responsible for the far-infrared brightness of 3C 207. Our analysis demonstrates that nonthermal …

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Effects Of Interaction Induced Activities In Hickson Compact Groups: Co And Fir Study, L Verdes-Montenegro, Min S. Yun, J Perea, A Del Olmo, P T P Ho Jan 1998

Effects Of Interaction Induced Activities In Hickson Compact Groups: Co And Fir Study, L Verdes-Montenegro, Min S. Yun, J Perea, A Del Olmo, P T P Ho

Min S. Yun

A study of 2.6 mm CO J = 1 → 0 and far-infrared (FIR) emission in a distance-limited (z < 0.03) complete sample of Hickson compact group (HCG) galaxies was conducted in order to examine the effects of their unique environment on the interstellar medium of component galaxies and to search for a possible enhancement of star formation and nuclear activity. Ubiquitous tidal interactions in these dense groups would predict enhanced activities among the HCG galaxies compared to isolated galaxies. Instead, their CO and FIR properties (thus, "star formation efficiency") are surprisingly similar to isolated spirals. The CO data for 80 HCG galaxies presented here (including 10 obtained from the literature) indicate that the spirals globally show the same H2 content as the isolated comparison sample, although 20% are deficient in CO emission. Because of their large optical luminosity, low metallicity is not likely the main cause for the low CO luminosity. The CO deficiency appears linked with the group evolution, and gas exhaustion through past star formation and removal of the external gas reserve by tidal stripping of the outer H I disk offer a possible explanation. The IRAS data for the entire redshift-limited complete sample of 161 HCG galaxies were reanalyzed using ADDSCAN/SCANPI, improving the sensitivity by a factor of 3-5 over the existing Point Source Catalog (PSC) and resolving better the contribution from individual galaxies. The new analysis of the IRAS data confirms the previous suggestion that FIR emission in HCG galaxies is similar to isolated, Virgo Cluster, and weakly interacting galaxies. Their H2 and FIR characteristics yield a star formation efficiency that is similar to that of these comparison samples. A factor 2 enhancement in the 25-100 μm flux ratio among the HCG spirals is found, which suggests intense localized nuclear starburst activity similar to that of H II galaxies. A number of early-type galaxies in HCGs are detected in CO and FIR, lending further support to the idea that tidal interactions and tidally induced evolution of the groups and member galaxies are important in our sample.

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Co J = 3-2 Emission In The Radio Galaxy 53w002 At Z = 2.394, N Z. Scoville, Min S. Yun, R A. Windhorst, W C. Keel, L Armus Aug 1997

Co J = 3-2 Emission In The Radio Galaxy 53w002 At Z = 2.394, N Z. Scoville, Min S. Yun, R A. Windhorst, W C. Keel, L Armus

Min S. Yun

We report a sensitive search for redshifted CO J = 3-2 emission from the weak radio galaxy 53W002 at z = 2.394. Maps at resolutions of 3'' and 235 km s-1 show a significant emission peak within 0farcs5 of the optical and radio continuum peaks. The measured narrowband flux is approximately 10 times the extrapolated centimeter-wavelength nonthermal radio continuum expected at 101.9 GHz and exhibits a spectral profile implying a 540 km s-1 width (FWHM) at a systemic redshift z = 2.394 ± 0.001 for CO (3-2). This emission has a total integrated flux of 1.51 ± 0.2 Jy km …

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Arcsecond Imaging Of Co Emission In The Nucleus Of Arp 220, N Z. Scoville, Min S. Yun, P M. Bryant Aug 1997

Arcsecond Imaging Of Co Emission In The Nucleus Of Arp 220, N Z. Scoville, Min S. Yun, P M. Bryant

Min S. Yun

We report high-resolution (1A) imaging of CO (2È1) and dust continuum emission in the ultraluminous galaxy Arp 220. The CO (1È0) line was also imaged at 2A resolution for comparison. Both data sets recover essentially all of the observed single-dish line emission. Our aperture synthesis maps reveal for the Ðrst time, multiple components in the dense gas: peaks corresponding to each of the double nuclei (separated by 0A.95 at P.A.\101¡) seen in the near infrared and radio continuum and a more extended disklike structure at P.A.\53¡, similar to the dust lane seen in optical images. Approximately two-thirds of the total …

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Resolution And Kinematics Of Molecular Hydrogen In The Cloverleaf Gravitational Lens, Min S. Yun, N Z. Scoville, J J. Carrasco, R D. Blandford Apr 1997

Resolution And Kinematics Of Molecular Hydrogen In The Cloverleaf Gravitational Lens, Min S. Yun, N Z. Scoville, J J. Carrasco, R D. Blandford

Min S. Yun

Gravitational lenses have long been advertised as primitive telescopes, capable of magnifying cosmologically distant sources. In this Letter we present new, 0"9 resolution CO (7– 6) observations of the z 5 2.56 Cloverleaf quasar (H14131117) and spatially resolved images. By modeling the gravitational lens, we infer a size scale of 0"3 (11 kpc) for the molecular gas structure surrounding the quasar, and the gas has a kinematic structure roughly consistent with a rotating disk. The observed properties of the CO-emitting gas are similar to the nuclear starburst complexes found in the infrared luminous galaxies in the local universe, and metal …

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Molecular Gas And Infrared Emission In Hcg 31 And Hcg 92 (Stephan's Quintet) And Tidal Interactions In Compact Group Environment, Min S. Yun, L Verdes-Montenegro, A Del Olmo, J Perea Jan 1997

Molecular Gas And Infrared Emission In Hcg 31 And Hcg 92 (Stephan's Quintet) And Tidal Interactions In Compact Group Environment, Min S. Yun, L Verdes-Montenegro, A Del Olmo, J Perea

Min S. Yun

We present the interferometric measurements of 2.6 mm CO (J 5 13 0) emission (uFWHM 1 50) and the analysis of IRAS HIRES images of two Hickson compact groups HCG 31 and HCG 92 (“Stephan’s Quintet”). The far-infrared (FIR) emission is concentrated to a single region in HCG 31 while it is clearly extended and peaks near the group center in HCG 92. CO emission is weak in HCG 31, and the brightest peak occurs in the overlap region between the galaxies A and C. CO emission is detected only in galaxy C (NGC 7319) in HCG 92, and the …

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Nonlinear Dependence Of Lb On Lfir And Mh2 Among Spiral Galaxies And The Effects Of Tidal Interaction, J Perea, A Del Olmo, L Verdes-Montenegro, Min S. Yun Jan 1997

Nonlinear Dependence Of Lb On Lfir And Mh2 Among Spiral Galaxies And The Effects Of Tidal Interaction, J Perea, A Del Olmo, L Verdes-Montenegro, Min S. Yun

Min S. Yun

Through the study of a carefully selected sample of isolated spiral galaxies, we have established that two important global physical quantities for tracing star-forming activities, LFIR and MH2, have a nonlinear dependence on another commonly cited global quantity, LB. Furthermore, we show that simple power-law relations can effectively describe these nonlinear relations for spiral galaxies spanning 4 orders of magnitude in FIR and MH2, and nearly 3 orders of magnitude in LB. While the existence of a nonlinear dependence of MH2 (assuming a constant CO-to-H2 conversion) and LFIR on optical luminosity (LB) has been previously noted in the literature, an …

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The H Ii Region Complex G5.48-0.24: Radio Continuum, H I, And Co Observations, Bon-Chul Koo, Kee-Tae Kim, Ho-Gyu Lee, Min S. Yun, Paul T P Ho Jan 1996

The H Ii Region Complex G5.48-0.24: Radio Continuum, H I, And Co Observations, Bon-Chul Koo, Kee-Tae Kim, Ho-Gyu Lee, Min S. Yun, Paul T P Ho

Min S. Yun

We have carried out VLA radio continuum (6 and 20cm), VLA HI 21cm line, and 13CO J = 1 --> 0 line observations of the Galactic H II region G5.48-0.24. We present the continuum maps at 21 cm with 50" resolution and at 6 and 20 cm with 5" resolution. The radio continuum maps show that the H II region is composed of a bright component immersed in a diffuse emission of 6' (or 21 pc) radius. The bright component has a compact (0.7 pc) core surrounded by an extended (3.4 pc) halo. According to Wood & Churchwell (1989), the …

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Extended Molecular Gas Distribution In Mrk 273 And Merger-Luminosity Evolution, Min S. Yun, N Z. Scoville Oct 1995

Extended Molecular Gas Distribution In Mrk 273 And Merger-Luminosity Evolution, Min S. Yun, N Z. Scoville

Min S. Yun

We present the first interferometric measurement of CO emission (θ ~ 2'') from the ultraluminous infrared galaxy Mrk 273. A total H2 mass of 3.6 × 1010 Msun is inferred from the CO observations, half of which belongs to an extended component with deconvolved size 5.1 × 2.5 kpc. In addition, an unresolved molecular gas complex is found to be coincident with the optical nucleus. The inferred H2 mass, size (R ~ 380 pc), and mean surface mass density (ΣH2 ≥ 4 × 104 Msun pc-3) of this complex, as well as the IR luminosity, are very similar to those …

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Extended Molecular Gas In Fsc 10214+4724, N Z. Scoville, Min S. Yun, R L. Brown, P A. Vanden Bout Jan 1995

Extended Molecular Gas In Fsc 10214+4724, N Z. Scoville, Min S. Yun, R L. Brown, P A. Vanden Bout

Min S. Yun

e report high resolution imaging of the CO (3-2) emission in the luminous infrared source FSC 10214+4724 at z = 2.2853. Maps at resolutions of 2farcs3 × 3farcs0 and 45-90 km s-1 show the CO emission peak coinciding with those of Hα and radio continuum. Two components are identified in the CO emission: an unresolved core and an extended source (~1farcs9 × 4farcs4)—elongated southeast-northwest. The implied size is 9 × 24 kpc for H0 = 75 km s-1 Mpc-1 and q0 = 0.5. The extent of the CO emission is significantly greater than that of either the optical or the …

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Vv 114: Making Of An Ultraluminous Galaxy?, Min S. Yun, N Z. Scoville, R A. Knop Aug 1994

Vv 114: Making Of An Ultraluminous Galaxy?, Min S. Yun, N Z. Scoville, R A. Knop

Min S. Yun

High-resolution (Theta = 4 arcseconds .4 x 3 arcseconds .1) CO observations of the IR luminous system VV 114 (IC 1623) using the Owens Valley Millimeter array reveal 5.1 x 1010 Solar masses of H2 in a 5.9 x 3.1 kpc (15 arcseconds x 8 arcseconds) bar with two 4-6 kpc long tails (D = 80 Mpc for H 0= 75). The wide separation (6 kpc) of the merging optical galaxies, the extended gas distribution, and the noncircular gas kinematics suggest that VV 114 is in an early stage of a gas-rich merger. The concentration of gas and its dominance …

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Interaction Between The Supernova Remnant Ctb 80 And The Ambient Interstellar Medium: Hi And Co Observations, Bon-Chul Koo, Min S. Yun, Paul T P Ho, Youngung Lee Nov 1993

Interaction Between The Supernova Remnant Ctb 80 And The Ambient Interstellar Medium: Hi And Co Observations, Bon-Chul Koo, Min S. Yun, Paul T P Ho, Youngung Lee

Min S. Yun

No abstract provided.

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