arXiv subjects

Philip M. Hinz

Publications and source records attributed to Philip M. Hinz.

76 records · Page 5Linked to original sources

arXiv2005

SDSSJ102111.02+491330.4: A Newly Discovered Gravitationally Lensed Quasar

We report follow-up observations of two gravitational lens candidates identified in the Sloan Digital Sky Survey (SDSS) dataset. We have confirmed that SDSS J102111.02+491330.4 is a previously unknown gravitationally lensed quasar. This lens system exhibits two images of a $z = 1.72$ quasar, with an image separation of $1{\farcs}14 \pm 0.04$. Optical and near-IR imaging of the system reveals the presence of the lensing galaxy between the two quasar images. Observations of SDSS J112012.12+671116.0 indicate that it is more likely a binary quasar than a gravitational lens. This system has two quasars at a redshift of $z = 1.49$, with an angular separation of $1{\farcs}49 \pm 0.02$. However, the two quasars have markedly different SEDs and no lens galaxy is apparent in optical and near-IR images of this system. We also present a list of 31 SDSS lens candidates which follow-up observations have confirmed are \textit{not} gravitational lenses.

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arXiv2004

Constraining the Lifetime of Circumstellar Disks in the Terrestrial Planet Zone: A Mid-IR Survey of the 30-Myr-old Tucana-Horologium Association

We have conducted an N-band survey of 14 young stars in the ~30 Myr-old Tucana-Horologium Association to search for evidence of warm, circumstellar dust disks. Using the MIRAC-BLINC camera on the Magellan I (Baade) 6.5-m telescope, we find that none of the stars have a statistically significant N-band excess compared to the predicted stellar photospheric flux. Using three different sets of assumptions, this null result rules out the existence of the following around these post-T Tauri stars: (a) optically-thick disks with inner hole radii of ~<0.1 AU, (b) optically-thin disks with masses of >10^{-6} M_Earth (in ~1-micron-sized grains) within ~<10 AU of these stars, (c) scaled-up analogs of the solar system zodiacal dust cloud with >4000X the emitting area. Our survey was sensitive to dust disks in the terrestrial planet zone with fractional luminosity of log(L_{dust}/L_{star}) ~ 10^{-2.9}, yet none were found. Combined with results from previous surveys, these data suggest that circumstellar dust disks become so optically-thin as to be undetectable at N-band before age ~20 Myr. We also present N-band photometry for several members of other young associations and a subsample of targets that will be observed with Spitzer Space Telescope by the Formation and Evolution of Planetary Systems (FEPS) Legacy Science Program. Lastly, we present an absolute calibration of MIRAC-BLINC for four filters (L, N, 11.6, and Q_s) on the Cohen-Walker-Witteborn system.

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arXiv2003

Klio: A 5 micron camera for the detection of giant exoplanets

We plan to take advantage of the unprecedented combination of low thermal background and high resolution provided by the 6.5m MMT's adaptive secondary mirror, to target the 3-5 micron atmospheric window where giant planets are expected to be anomalously bright. We are in the process of building a 3-5 micron coronograph that is predicted to be sensitive to planets as close as 0.4 arcsec to the parent star. We expect to be able to detect giant planets down to 5 times Jupiter's mass for a 1 Gyr old system at 10 pc. We plan to carry out a survey which is complementary to the radial velocity detections of planets and constructed to characterize the prevalence and distribution of giant planets around nearby, Sun-like stars.

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arXiv2001

Constraints on Disk Sizes Around Young Intermediate-Mass Stars: Nulling Interferometric Observations of Herbig Ae Objects

Physical models of circumstellar disks surrounding pre-main sequence stars are currently constrained primarily by the spectral energy distribution (SED) of the system. Here we present first results from a survey of nearby Herbig Ae stars using nulling interferometry. We measure the spatial extent of the mid-IR emission for the stars HD 150193, HD 163296, and HD 179218. The results indicate the size of mid-infrared emission around Herbig Ae stars may be much smaller than current models predict. The observations constrain ~90% of the 10 micron flux to be within an approximately 20 AU diameter region, providing significant spatial limits for disk models. These results demonstrate the scientific potential for nulling interferometry to study circumstellar disks with better spatial discernment than is possible with standard mid-infrared imaging.

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