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cso:outreach:seminar [2013-09-07 02:50]
sradford [CSO Science Seminars]
cso:outreach:seminar [2013-09-07 02:50] (current)
sradford [CSO Science Seminars]
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 +====== CSO Science Seminars ======
 +CSO science seminars are held occasionally in the conference room at the [[cso:​logistics:​contacts|CSO office in Hilo]]. Please join us!
 +===== 2012 =====
 +=== 2012-02-27 ===
 +Dr. Steve Padin (Caltech) \\
 +Monday, 2012 June 27 at 4:00 pm
 +CCAT will be a 25 m diameter telescope equipped with cameras and spectrometers operating in the 0.2-2 mm wavelength range. ​
 +CCAT will be large enough to resolve essentially all the submillimeter background at 350 µm, and its small beam will yield source positions with arcsecond accuracy to support follow-up observations. ​
 +CCAT will be located on Cerro Chajnantor in northern Chile. ​
 +The combination of an efficient telescope, an excellent site, and wide-field cameras and spectrometers will make CCAT a uniquely powerful survey instrument.
 +===== 2011 =====
 +=== 2011-06-09 ===
 +ZEUS-2: A Grating Spectrometer Optimized For Observations of High-Z Galaxies and Warm Molecular Gas In Nearby Galaxies\\
 +Dr. Thomas Nikola (Cornell University) \\
 +Thursday, 2011 June 9 at 4:00 pm 
 +Observation of far-infrared line emission that is redshifted into the 
 +submillimeter regime provides a unique glimpse at the star-formation ​
 +and nuclear activity of high-z galaxies. For example, the [CII] 158 
 +micron and [OI] emission probe the properties of gas heated by recent ​
 +star formation, while the [OIII] 88 micron and [NII] lines trace ionized ​
 +gas that is excited either by star formation or nuclear activity. These 
 +observations require the most sensitive and state-of-the-art instruments.
 +Warm molecular gas is intimately linked to kinematic and radiative ​
 +processes in galaxies, like shock excitation in cloud-cloud collisions, ​
 +star formation, or nuclear activity. These processes also drive galaxy ​
 +evolution. Since each of the mechanisms (e.g. PDR, XDR, shocks) that 
 +heat the molecular gas imprints a distinct signature on the mid- and 
 +high-J CO transitions these lines are excellent tools to study the interplay ​
 +between global and local galactic properties, hence the evolution of galaxies.
 +ZEUS-2 is a submillimeter grating spectrometer optimized for these 
 +observations. It can observe multiple lines simultaneously and also 
 +provides spatial information in extended objects. In this presentation ​
 +I will give an overview of the instrument, its current status, and the 
 +science cases that drive the requirements of ZEUS-2. ​
 +=== 2011-05-16 ===
 +Protostellar Outflows and Clustered Star Formation: The Case of Serpens South \\
 +Dr. Fumitaka Nakamura (National Astronomical Observatory of Japan) \\
 +Monday, 2011 May 16 at 3:00 pm 
 +I will briefly present some recent results of our numerical simulations of 
 +cluster formation including protostellar outflow feedback, discussing the 
 +importance of outflow feedback in clustered star formation. Then, as an 
 +example, I will present some recent results of our CO J = 3 - 2 observations ​
 +toward a nearby embedded cluster, Serpens South, newly discovered by 
 +Spitzer legacy survey as an infrared dark cloud. Our CO J = 3 - 2 map 
 +reveals that many outflows are crowded in the dense cluster-forming clump. ​
 +I will discuss how the outflow feedback influences the dynamics of the 
 +cluster-forming region.
 +=== 2011-05-09 ===
 +The Multiwavelength Submillimeter Inductance Camera (MUSIC): A New Facility Instrument at the CSO \\
 +Nicole Czakon (Caltech) \\ 
 +Friday, 2011 May 9 at 4:00 pm \\
 +An insatiable appetite for large-format,​ kilo-pixel arrays in the 
 +millimeter/​submillimeter astrophysics community has motivated ​
 +the development of a novel detecting element--the millimeter-wave ​
 +kinetic inductance detector (MKID). Our team is in the final stages ​
 +of constructing an MKID camera called MUSIC. The camera will 
 +have 576 spatial pixels, each simultaneously sensitive to four 
 +wavelengths:​ .87, 1.0, 1.3, and 2.0 mm.  An MKID uses a low 
 +gap-energy superconducting film to provide the inductive contribution ​
 +to a resonant LC circuit. As the superconductor absorbs photons, its 
 +kinetic inductance changes, and detection occurs by monitoring the 
 +resulting shift in resonant frequency. By tuning each detector to a 
 +different frequency, hundreds of MKIDs can be coupled to a single ​
 +microwave transmission line. Readout complexity is thus transferred ​
 +to room temperature,​ where we have developed an FPGA-based readout, ​
 +thanks, in part, to hardware and software from the CASPER-ROACH ​
 +collaboration. ​ Commissioning at the CSO is expected to begin in Winter ​
 +2011/2012. I will review the principles of MKID theory and design, how 
 +we read them out, and give an update on the current status of the instrument.
 +===== 2009 =====
 +=== 2009-05-27 ===
 +SMA and CSO Observations of Magnetic Fields in Star-forming Regions\\
 +Dr. Shih-Ping Lai (National Tsing Hua University) \\
 +Wednesday, 2011 May 27 at 11:00 am \\
 +In this talk, we will present the SMA and CSO polarization projects we
 +have been working on: (1) Evolution of Magnetic Fields from Class 0 to
 +Class II Stage, (2) Toroidal Magnetic Field Revealed in the
 +Protostellar Disk of NGC1333 IRAS 4A, and (3) Constructing the
 +Magnetic Field Geometry along line of sight with Multi-wavelength
 +Polarization Observations. ​ The main goal of these projects is to
 +investigate the role magnetic field plays during star formation.
 +===== 2008 =====
 +=== 2008-12-08 ===
 +Observational Determination of the Turbulent Ambipolar Diffusion Scale in Molecular Clouds\\
 +Prof. Martin Houde (The University of Western Ontario)\\
 +Monday, 2008 December 8at 11:00 am \\
 +I will present a study of the turbulent velocity dispersion spectra (versus length ​
 +scale) for the coexistent HCN and HCO+ molecular species in the M17 star-forming ​
 +molecular cloud. I will show that the observed downward shift of the ion's spectrum ​
 +relative to that of the neutral is readily explained by the existence of an ambipolar ​
 +diffusion scale below which the motions of the ion and neutral components of the 
 +gas decouple from one another. For M17, this decoupling scale is measured to be 
 +1.8 mpc; this is the first time that this fundamental quantity is determined observationally. ​
 +Moreover, this result is in excellent agreement with previous theoretical predictions. ​
 +I will also demonstrate how these observations can be used to estimate the strength of 
 +the plane-of-the-sky component of the embedded magnetic field in a completely novel way.
 +=== 2008-12-01 ===
 +ZEUS on the CSO: Probing the Gas in Active Regions in ULIRGs and High-Redshift Galaxies\\
 +Dr. Thomas Nikola (The Cornell University)\\
 +2008 December 1 at 11:00 am\\
 +The star formation rate per unit volume shows strong evolution over the history of 
 +the Universe. ​ This suggests a change of the gas properties in star formation regions or
 +a variation of their size or both. We have built a grating spectrometer,​ ZEUS, for the 
 +submillimeter wavelength regime to investigate the physical properties of the gas in
 +regions of enhanced star formation in ULIRGs and distant galaxies. ​ With our instrument ​
 +we observe redshifted far-infrared fine structure lines, especially the 158 micron [CII] line, 
 +mid-J CO lines, and the [CI] 371 micron fine structure line to trace the gas properties in 
 +the star forming regions. ​ In this presentation I will introduce our grating spectrometer, ​
 +ZEUS, and give an overview of the results that we have obtained using our instrument
 +on the CSO.
 +=== 2008-07-18 ===
 +Hydrogen Isocyanide in the ISM and Comets\\
 +Dr. Darek Lis (California Institute of Technology) \\
 +2008 July 18 at 3:00 pm\\
 +I discuss the current understanding of the origin of hydrogen
 +isocyanide in the interstellar medium and comets. HNC, first detected
 +in comet Hyakutake by means of submillimeter spectroscopy,​ has now
 +been observed in a dozen moderately bright comets, not including the
 +very active comets Hale-Bopp and McNaught. The existing data suggest
 +that HNC production has to be efficient in the inner coma, just as the
 +material leaves the nucleus. The process has to be temperature
 +dependent to explain the observed variation in the HNC/HCN abundance
 +ratio with the heliocentric distance. Thermal degradation of
 +macromolecules or polymers produced from ammonia and carbon compounds,
 +such as acetylene, methane, or ethane appears to be a process
 +consistent with the existing observational data, including the very
 +low HNC/HCN ratio measured recently in comet 73P/​Schwassmann-
 +Wachmann 3.
 +=== 2008-04-28 ===
 +Evolution and Astrophysics of Distant Ultraluminous Galaxies\\
 +Prof. Andrew Blain (California Institute of Technology) \\
 +2008 April 28 at 11:00\\
 +The most luminous high-redshift galaxies are dominated by energy  ​
 +production at far-infrared wavelengths. Selected with poor angular  ​
 +resolution using ground-based submillimeter and space-borne ​
 +far-infrared telescopes, they are a crucial component of our understanding  ​
 +of galaxy formation. However, understanding their properties requires  ​
 +arduous follow-up observations from radio to X-ray. I will describe  ​
 +progress with understanding the evolution and astrophysics of these  ​
 +galaxies, which trace the top end of the galaxy luminosity function,  ​
 +and highlight some forthcoming opportunities using NASA's WISE, and  ​
 +=== 2008-02-15 ===
 +Extragalactic Science with APEX and SHARCII/​CSO\\
 +Dr. Attila Kovacs (Max Planck Institute for Radio Astronomy) \\
 +2008 February 15 at 3:00 pm\\
 +I will provide a brief overview of the extragalactic science projects currently under 
 +way at the APEX telescope in Chile, with special focus on the early extragalactic ​
 +results from the new 295-pixel bolometer camera LABOCA. ​  In the second part, 
 +for a more local flavor, I will present the results from a follow-up study of submillimeter ​
 +galaxies with the SHARCII camera at the CSO. The SHARCII data allows the first 
 +firm constraints of the dust-temperatures and bolometric luminosities for this population ​
 +of high-z galaxies. They also allow the testing of the radio to far-infrared correlation ​
 +at the higher redshifts.
 +===== 2007 =====
 +=== 2007-10-12 ===
 +Hydrogenated/​Deuterated Species; Observations and Models\\
 +Dr. Evelyne Roueff (Observatoire de Paris) \\
 +2007 October 12 at 11:00 am\\
 +Thirty interstellar and circumstellar molecules containing deuterium  ​
 +have been detected to date, with several doubly- and triply-deuterated
 +isotopologues. The fractionation ratio, defined as the ratio of the  ​
 +column density of a deuterated molecule to its hydrogen counterpart,​ is  ​
 +often found to be orders of magnitude higher than the elemental abundance ​
 +ratio, which is typically from 1.5 × 10<​sup>​−5</​sup>​ to 2.3 × 10<​sup>​−5</​sup>​. ​ This deuterium ​
 +enhancement results from chemical processes, which may involve both 
 +gas-phase [1,2] and surface reactions [3].  Observational data and detailed ​
 +gas-phase models will be reviewed. Particular emphasis will be put on 
 +ortho/ para chemistry and on the role of deuterated hydrocarbons as vectors ​
 +for deuteration. We also discuss the consequences of local elemental  ​
 +deuterium enhancements on molecular fractionation ratios [4].
 +[1] Roberts, H., Herbst, E., Millar, T.J., 2003, ApJ 591, L41,\\
 +Roberts, H., Herbst, E., Millar, T.J., 2004, A&A 424, 905\\
 +[2] Roueff, E. Lis, D., van der Tak, F.F.S., Gerin, M., Goldsmith,  ​
 +P., 2005, A&A 438, 585\\
 +[3] Lishat, A., Biham, O., Herbst, E., 2004, MNRAS 348, 1055\\
 +[4] Roueff, E., Herbst, E., Lis, D., Phillips, T., 2007, ApJL in press.
 +=== 2007-10-04 ===
 +Update to the CSO Submillimeter Active Optics System\\
 +Melanie Leong (Caltech Submillimeter Observatory) \\
 +2007 October 4 at 4:00 pm\\
 +The Caltech Submillimeter Observatory'​s (CSO'​s) Submillimeter Active Optics System is an open loop real time system that corrects the dish surface figure for imperfections and gravitational deformations as the dish moves in elevation during observations. ​ This improvement in the telescope'​s aperture efficiency aids observations in the shorter wavelengths,​ specifically in the 350-µm-wavelength range. ​ Simplicity, attention to detail, and perseverance were the keys to the success of this unique system.
 +The CSO's primary is part of a Robert Leighton telescope design, consisting of 84 hexagonal panels forming a 10.4-meter primary dish. There are 99 steel rod standoffs that interface the backing structure to the back of the primary. ​ It is on these standoffs where heating and cooling assemblies are mounted and implemented to lengthen or shorten the standoffs to desired lengths.
 +Holography maps were used to build a correction table to determine the amount of length and location of change on the primary. ​ Implementation of thermal electric devices enables the adjustability for each standoff.
 +The CSO's Submillimeter Active Optics System has been in use since February 2003.  Since then, new discoveries of distant galaxies or sharper detail of known objects have been obtained. ​ These will be presented during this talk. 
 +By holography, the smoothness of the dish is better than 10 microns RMS from zenith angles of 5 to 63 degrees. ​ The present percent improvement to the primary'​s surface is as high as 74%, with an average of 60% improvement. ​
 +Preliminary performance improvements have been found to compensate for SHARCII'​s new mounting location, from the Cassegrain focus to a second Nasmyth location, N2.  SHARCII is an 384 pixel submillimeter high angular resolution camera.
 +=== 2007-07-20 ===
 +Star Formation: From Cores to Disks\\
 +Prof. Neal J. EVANS II (The Univeristy of Texas at Austin)\\
 +2007 July 20 at 11 am\\ 
 +I will highlight recent developments in the early stages of star formation. ​
 +Observations with the Spitzer Space Telescope and complementary data 
 +at other wavelengths have provided more complete samples of star-forming ​
 +regions. These provide constraints on theoretical models of the origin of the 
 +initial mass function and evolutionary stages. The early stages of star 
 +formation include the separation of dense cores from the background ​
 +molecular cloud, the evolution before point source formation, the infall ​
 +onto the central source, and the formation of the disk. These events are 
 +usually associated with changes in the SED associated with the Class System. ​
 +The large sample available from the Cores to Disks (c2d) program provides ​
 +good statistics on the numbers of objects in various stages, and these can 
 +be used to estimate timescales.
 +=== 2007-06-27 ===
 +H<​sub>​3</​sub><​sup>​+</​sup>,​ a new astrophysical probe, and revelation of warm and 
 +diffuse gas near the Galactic center\\
 +Prof. Takeshi OKA  (University of Chicago)\\
 +2007 June 27 at 11:00 am\\
 +With a super-massive black hole at the core, the region near the
 +Galactic center is the hub of activity. Emissions from radio to X-rays and
 +the densities of stars and gas all peak in the region. It also harbors the
 +Central Molecular Zone (CMZ), a region of radius ~ 200 pc which has
 +the highest concentration of molecules in the Galaxy. Our infrared
 +spectroscopic observations in the last five years have shown that
 +sightlines toward the CMZ have H<​sub>​3</​sub><​sup>​+</​sup>​ column densities that are
 +~ 10 times higher than the highest observed in the Galactic disk.
 +Using this richness of H<​sub>​3</​sub><​sup>​+</​sup>​ with its unique characteristics as an
 +astrophysical probe, a new category of gas with high temperature
 +(~ 250 K) and low density (~< 100 cm<​sup>​-3</​sup>​) has been revealed in the
 +CMZ. Our observations of 8 sightlines toward bright infrared YSOs by
 +the UKIRT, Subaru, Gemini South, and VLT and their analyses suggest
 +that the gas is ubiquitous and has a high volume filling factor in the
 +CMZ. The relation between this newly found gas and previously known,
 +i. e., the cold (~ 50 K) and high density (~> 10<​sup>​4</​sup>​) cm<​sup>​-3</​sup>​) gas observed
 +by radio emission of CO, CS, HCN and other molecules, the hot (10<​sup>​4-6</​sup>​
 +K) gas with high electron densities (~ 10 cm<​sup>​-3</​sup>​) inferred from hyper-strong
 +radio-wave scattering, and the ultra-hot (10<​sup>​7-8</​sup>​K) gas emitting
 +X-rays is speculated.
 +=== 2007-06-07 ===
 +Does the Galactic Magnetic Field Anchor in Turbulent Giant
 +Molecular Clouds?\\
 +Dr. Huabai LI (Harvard-Smithsonian Center for Astrophysics)\\
 +2007 June 7 at 11:00 am\\
 +Various mechanisms of supporting self-gravitating interstellar clouds and
 +regulating star formation have been invoked. Among which, the relative
 +importance between turbulence and magnetic fields has been long under
 +debated, largely owing to the lack of observational constraints on cloud
 +formation theories. ​ The recent development of Submillimeter polarimetry
 +offers a chance to map the field morphology from the bulk volume of a
 +molecular cloud. By comparing the observed morphology with those from 
 +MHD simulations,​ we can estimate magnetic field strength relative to turbulence.
 +I will present the data collected so far, and future observation plans with
 +CSO and SMA, along with an introduction of the polarimeters used in these
 +two observatories.
cso/outreach/seminar.txt · Last modified: 2013-09-07 02:50 by sradford
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