Nielsen, Eric L., Close, Laird M.
We expand on the results of Nielsen et al. (2008), using the null result for giant extrasolar planets around the 118 target stars from the VLT NACO H and Ks band planet search (Masciadri et al....
On the Apparent Orbital Inclination Change of the Extrasolar Transiting Planet TrES-2b (2009)
Scuderi, Louis J., Dittmann, Jason A., Males, Jared R., Green, Elizabeth M., Close, Laird M.
On June 15, 2009 UT the transit of TrES-2b was detected using the University of Arizona's 1.55 meter Kuiper Telescope with 2.0-2.5 millimag RMS accuracy in the I-band. We find a central transit time...
Dittmann, Jason A., Close, Laird M., Green, Elizabeth M., Fenwick, Mike
There have been numerous reports of anomalies during transits of the planet TrES-1b. Recently, Rabus and coworkers' analysis of HST observations lead them to claim brightening anomalies during...
Follow-up Observations of the Neptune Mass Transiting Extrasolar Planet HAT-P-11b (2009)
Dittmann, Jason A., Close, Laird M., Green, Elizabeth M., Scuderi, Louis J., Males, Jared R.
We have confirmed the existence of the transiting super Neptune extrasolar planet HAT-P-11b. On May 1, 2009 UT the transit of HAT-P-11b was detected at the University of Arizona's 1.55m Kuiper...
A Search for Wide Companions to the Extrasolar Planetary System HR 8799 (2009)
Close, Laird M., Males, Jared R.
The extrasolar planetary system around HR 8799 is the first multiplanet system ever imaged. It is also, by a wide margin, the highest mass system with >27 Jupiters of planetary mass past 25 AU. This...
NICI: combining coronagraphy, ADI, and SDI (2008)
Artigau, Etienne, Biller, Beth A., Wahhaj, Zahed, Hartung, Markus, Hayward, Thomas L., Close, Laird M., ...
The Near-Infrared Coronagraphic Imager (NICI) is a high-contrast AO imager at the Gemini South telescope. The camera includes a coronagraphic mask and dual channel imaging for Spectral Differential...
Observing Strategies for the NICI Campaign to Directly Image Extrasolar Planets (2008)
Biller, Beth, Artigau, Etienne, Wahhaj, Zahed, Hartung, Markus, Liu, Michael, Close, Laird M., ...
We discuss observing strategy for the Near Infrared Coronagraphic Imager (NICI) on the 8-m Gemini South telescope. NICI combines a number of techniques to attenuate starlight and suppress...
Contrast Enhancement of Binary Star System Using an Optical Vortex Coronagraph (2008)
Swartzlander, Grover A., Ford, Erin L., Abdul-Malik, Rukiah S., Close, Laird M., Peters, Mary Anne, ...
Using an optical vortex coronagraph and simple adaptive optics techniques we have made the first convincing demonstration of an optical vortex coronagraph that is coupled to a star gazing telescope....
Dense molecular gas in a young cluster around MWC 1080: rule of the massive star (2008)
Wang, Shiya, Looney, Leslie W., Brandner, Wolfgang, Close, Laird M.
We present CS J=2-->1, 13CO J=1-->0, and C18O J=1-->0, observations with the 10 element Berkeley Illinois Maryland Association (BIMA) array toward the young cluster around the Be star MWC 1080. These...
Nielsen, Eric L., Close, Laird M., Biller, Beth A., Masciadri, Elena, Lenzen, Rainer
We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast...
Astronomy with adaptive optics: experiences from the University of Hawaii AO program (2007)
Laird M. Close, Dan Potter, Claude Roddier, J. Elon Graves
The University of Hawaii adaptive optics (AO) group has been actively carrying out astronomical AO observations for the last four years. The UHAO group and our collaborators have utilized the...
Daniel Potter, Laird M. Close, Claude Roddier, J. E. Graves, Malcolm Northcott
. We have obtained J band (1.2 µm) polarimetry observations of the circumbinary disk around UY Aurigae with the University of Hawaii 36 element adaptive optics instrument, Hokupa'a, at the 3.6...
Astronomy with adaptive optics: experiences from the University of Hawaii AO program (2007)
Laird M. Close, Dan Potter, Claude Roddier, J. Elon Graves
The University of Hawaii adaptive optics (AO) group has been actively carrying out astronomical AO observations for the last four years. The UHAO group and our collaborators have utilized the...
Proc. SPIE 3353, March 23-26 1998, Kona, Hawaii (2007)
Wa Ii, Laird M. Close, Claude Roddier, J. Elon Graves, Malcolm Northcott, Dan Potter
The University of Hawaii adaptive optics (AO) group has been actively carrying out astronomical AO observations for the last four years. The UHAO group and our collaborators have utilized the...
PG 1700+518 Revisited: Adaptive Optics Imaging and a Revised Starburst Age for the Companion (2007)
Alan Stockton, Gabriela Canalizo, Laird M. Close
We present the results of adaptive-optics imaging of the z = 0:2923 QSO PG1700+518 in the J and H bands. The extension to the north of the QSO is clearly seen to be a discrete companion with a...
Dense Molecular Gas In A Young Cluster Around MWC 1080 -- Rule Of The Massive Star (2007)
Wang, Shiya, Looney, Leslie W., Brandner, Wolfgang, Close, Laird M.
We present CS $J = 2 \to 1$, $^{13}$CO $J = 1 \to 0$, and C$^{18}$O $J = 1 \to 0$, observations with the 10-element Berkeley Illinois Maryland Association (BIMA) Array toward the young cluster around...
Nielsen, Eric L., Close, Laird M., Biller, Beth A., Masciadri, Elena, Lenzen, Rainer
We examine the implications for the distribution of extrasolar planets based on the null results from two of the largest direct imaging surveys published to date. Combining the measured contrast...
The very nearby M/T dwarf binary SCR 1845-6357 (2007)
Kasper, Markus, Biller, Beth A., Burrows, Adam, Brandner, Wolfgang, Budaj, Jano, Close, Laird M.
The recently discovered star SCR 1845-6357 is the first late M/T dwarf binary discovered. SCR 1845 is a particular object due to its tight orbit (currently around 4 AU) and its proximity to the Sun...
Biller, Beth A., Close, Laird M., Masciadri, Elena, Nielsen, Eric, Lenzen, Rainer, Brandner, Wolfgang, ...
We present the results of a survey of 45 young (
Close, Laird M., Thatte, Niranjan, Nielsen, Eric L., Abuter, Roberto, Clarke, Fraser, Tecza, Matthias
We present new photometric and spectroscopic measurements for the unique, young, low-mass evolutionary track calibrator AB Dor C. While the new Ks photometry is similar to that previously published...
Thatte, Niranjan, Abuter, Roberto, Tecza, Matthias, Nielsen, Eric L., Clarke, Fraser J., Close, Laird M.
We present an extension of the spectral deconvolution method (Sparks & Ford 2002) to achieve very high contrast at small inner working radii. We apply the method to the specific case of ground based...
Discovery of a 66 mas Ultracool Binary with Laser Guide Star Adaptive Optics (2007)
Siegler, Nick, Close, Laird M., Burgasser, Adam J., Cruz, Kelle L., Marois, Christian, Macintosh, Bruce, ...
We present the discovery of 2MASS J21321145+1341584AB as a closely separated (0.066") very low-mass field dwarf binary resolved in the near-infrared by the Keck II Telescope using laser guide star...
Thatte, Niranjan, Abuter, Roberto, Tecza, Matthias, Nielsen, Eric L., Clarke, Fraser J., Close, Laird M.
Wang, Shiya, Looney, L. W., Brandner, Wolfgang, Close, Laird M.
Author Institution: Department of Astronomy, University of Illinois,; 1002 W. Green St., Urbana, IL 61801; Max-Planck-Institut fur Astronomie in Heidelberg, Germany; Steward Observatory, University...
Biller, Beth A., Close, Laird M., Masciadri, Elena, Nielsen, Eric, Lenzen, Rainer, Brandner, Wolfgang, ...
We present the results of a survey of 45 young (
A Reflective Gaussian Coronagraph for ExAO: Laboratory Performance (2006)
Park, Ryeojin, Close, Laird M., Siegler, Nick, Nielsen, Eric L., Stalcup, Thomas
We report laboratory results of a coronagraphic test bench to assess the intensity reduction differences between a "Gaussian" tapered focal plane coronagraphic mask and a classical hard-edged "Top...
Discovery of 9 New Companions to Nearby Young M Stars with the Altair AO System (2006)
Daemgen, Sebastian, Siegler, Nick, Reid, I. Neill, Close, Laird M.
We present results of a high-resolution, near-infrared survey of 41 nearby, young (= M6 very low-mass, VLM) populations. We find that the separation distribution of the binaries in this sample peaks...
Close, Laird M., Zuckerman, Ben, Song, Inseok, Barman, Travis, Marois, Christian, Rice, Emily L., ...
We imaged five objects near the star forming clouds of Ophiuchus with the Keck Laser Guide Star AO system. We resolved Allers et al. (2006)'s #11 (Oph 16222-2405) and #16 (Oph 16233-2402) into binary...
Biller, Beth A., Close, Laird M., Li, Aigen, Marengo, Massimo, Bieging, John H., Hinz, Phil M., ...
We imaged the symbiotic star CH Cyg and two PSF calibration stars using the unique 6.5m MMT deformable secondary adaptive optics system. Our high-resolution (FWHM=0.3"), very high Strehl (98%+-2%)...
Biller, Beth A., Close, Laird M., Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, Nielsen, Eric, ...
We discuss the instrumental and data reduction techniques used to suppress speckle noise with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT. SDI uses a double...
Biller, Beth A., Close, Laird M., Masciadri, Elena, Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, ...
We discuss the preliminary results of a survey of young ( 10 mag, Delta H > 11.5 mag for a T6 spectral type) at a separation of 0.5" from the primary star. With this degree of attenuation, we should...
Biller, Beth A., Close, Laird M., Masciadri, Elena, Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, ...
We discuss contrast limits obtained during a survey of young (10 mag, DeltaH>10.6 mag for a T6 spectral type) at a separation of 0.5" from the primary star. With this degree of attenuation, we can...
A Survey of close, young stars with SDI at the VLT and MMT (2006)
Biller, Beth A., Close, Laird M., Masciadri, Elena, Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, ...
Biller, Beth A., Close, Laird M., Lenzen, Rainer, Brandner, Wolfgang, McCarthy, Donald, Nielsen, Eric, ...
We discuss the instrumental and data reduction techniques used to suppress speckle noise with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT. SDI uses a quad filter to...
New observing modes of NACO (2005)
Kasper, Markus, Ageorges, Nancy, Boccaletti, Anthony, Brandner, Wolfgang, Close, Laird M., Davies, Ric, ...
Close, Laird M., Lenzen, Rainer, Guirado, Jose C., Nielsen, Eric L., Mamajek, Eric E., Brandner, Wolfgang, ...
Mass is the most fundamental parameter of a star, yet it is also one of the most difficult to measure directly. In general, astronomers estimate stellar masses by determining the luminosity and using...
Siegler, Nick, Close, Laird M., Cruz, Kelle L., Martin, Eduardo L., Reid, I. Neill
We present updated results of a high-resolution, magnitude limited (Ks20 AU) very low-mass (M_tot3 AU and mass ratios q>0.6. Within these instrumental sensitivities, these results support the overall...
Mid-Infrared Imaging of the Post-AGB Star AC Herculis with the MMT Adaptive Optics System (2003)
Close, Laird M., Biller, Beth, Hoffmann, William F., Hinz, Phil M., Bieging, John H., Wildi, Francois, ...
We utilized the MMT's unique deformable secondary adaptive optics system to produce high-resolution (FWHM=0.3"), very high Strehl mid-infrared (9.8, 11.7 & 18 micron) images of the post-AGB star AC...
Close, Laird M., Wildi, Francois, Lloyd-Hart, Michael, Brusa, Guido, Fisher, Don, Miller, Doug, ...
We present the first scientific images obtained with a deformable secondary mirror adaptive optics system. We utilized the 6.5m MMT AO system to produce high-resolution (FWHM=0.07'') near infrared...
Siegler, Nick, Close, Laird M., Mamajek, Eric E., Freed, Melanie
A survey of 30 nearby M6.0-M7.5 dwarfs with Ks0.8, Delta Ks20 AU) very low mass (M_{tot}3 AU. This binary frequency is less than the ~32% measured among early M dwarfs over the same separation range....
Close, Laird M., Siegler, Nick, Freed, Melanie, Biller, Beth
Use of the highly sensitive Hokupa'a/Gemini curvature wavefront sensor has allowed direct adaptive optics (AO) guiding on very low mass (VLM) stars with SpT=M8.0-L0.5. A survey of 39 such objects...
Discovery of a Tight Brown Dwarf Companion to the Low Mass Star LHS 2397a (2002)
Freed, Melanie, Close, Laird M., Siegler, Nick
Using the adaptive optics system, Hokupa'a, at Gemini-North, we have directly imaged a companion around the UKIRT faint standard M8 star, LHS 2397a (FS 129) at a separation of 2.96 AU. Near-Infrared...
Close, Laird M., Siegler, Nick, Potter, Dan, Brandner, Wolfgang, Liebert, James
Use of the highly sensitive Hokupa'a/Gemini curvature wavefront sensor has allowed for the first time direct adaptive optics (AO) guiding on M8-M9 very low mass (VLM) stars. An initial survey of 20...
PG 1700+518 Revisited: Adaptive Optics Imaging and a Revised Starburst Age for the Companion (1998)
Stockton, Alan, Canalizo, Gabriela, Close, Laird M.
We present the results of adaptive-optics imaging of the z=0.2923 QSO PG 1700+518 in the J and H bands. The extension to the north of the QSO is clearly seen to be a discrete companion with a...