Calibrating Type Ia Supernovae using the Planetary Nebula Luminosity Function I. Initial Results

We report the results of an [O III] lambda 5007 survey for planetary nebulae (PN) in five galaxies that were hosts of well-observed Type Ia supernovae: NGC 524, NGC 1316, NGC 1380, NGC 1448 and NGC 4526. The goals of this survey are to better quantify the zero-point of the maximum magnitude versus decline rate relation for supernovae Type Ia and to validate the insensitivity of Type Ia luminosity to parent stellar population using the host galaxy Hubble type as a surrogate. We detected a total of 45 planetary nebulae candidates in NGC 1316, 44 candidates in NGC 1380, and 94 candidates in NGC 4526. From these data, and the empirical planetary nebula luminosity function (PNLF), we derive distances of 17.9 +0.8/-0.9 Mpc, 16.1 +0.8/-1.1 Mpc, and 13.6 +1.3/-1.2 Mpc respectively. Our derived distance to NGC 4526 has a lower precision due to the likely presence of Virgo intracluster planetary nebulae in the foreground of this galaxy. In NGC 524 and NGC 1448 we detected no planetary nebulae candidates down to the limiting magnitudes of our observations. We present a formalism for setting realistic distance limits in these two cases, and derive robust lower limits of 20.9 Mpc and 15.8 Mpc, respectively. After combining these results with other distances from the PNLF, Cepheid, and Surface Brightness Fluctuations distance indicators, we calibrate the optical and near-infrared relations for supernovae Type Ia and we find that the Hubble constants derived from each of the three methods are broadly consistent, implying that the properties of supernovae Type Ia do not vary drastically as a function of stellar population. We determine a preliminary Hubble constant of H_0 = 77 +/- 3 (random) +/- 5 (systematic) km/s/Mpc for the PNLF, though more nearby galaxies with high-quality observations are clearly needed.Comment: 25 pages, 12 figures. Accepted for publication by the Astrophysical Journal. Figures degraded to comply with limit. Full paper is available at: http://www.as.ysu.edu/~jjfeldme/pnlf_Ia.pd

Search for nearby stars among proper motion stars selected by optical-to-infrared photometry. I. Discovery of LHS 2090 at spectroscopic distance of d=6pc

We present the discovery of a previously unknown very nearby star - LHS 2090 at a distance of only d=6 pc. In order to find nearby (i.e. d < 25 pc) red dwarfs, we re-identified high proper motion stars ($\mu >$ 0.18 arcsec/yr) from the NLTT catalogue (Luyten \cite{luyten7980}) in optical Digitized Sky Survey data for two different epochs and in the 2MASS data base. Only proper motion stars with large $R-K_s$ colour index and with relatively bright infrared magnitudes ($K_s<10$) were selected for follow-up spectroscopy. The low-resolution spectrum of LHS 2090 and its large proper motion (0.79 arcsec/yr) classify this star as an M6.5 dwarf. The resulting spectroscopic distance estimate from comparing the infrared $JHK_s$ magnitudes of LHS 2090 with absolute magnitudes of M6.5 dwarfs is $6.0\pm1.1$ pc assuming an uncertainty in absolute magnitude of $\pm$0.4 mag.Comment: 3 pages, 1 figure, accepted for publication in Astronomy and Astrophysics Letter

CORMASS: A Compact and Efficient NIR Spectrograph for Studying Low-Mass Objects

CorMASS (Cornell Massachusetts Slit Spectrograph) is a compact, low-resolution (R=300), double-pass prism cross-dispersed near-infrared (NIR) spectrograph in operation on the Palomar Observatory 60-inch telescope. Its 2-dimensional spectral format provides simultaneous coverage from lambda ~ 0.75 microns to lambda ~ 2.5 microns (z'JHK bands). A remotely operated cold flip mirror permits its NICMOS3 detector to function as a K_s slit viewer to assist object placement into the 2 arcsec x 15 arcsec slit. CorMASS was primarily designed for the rapid spectral classification of low-mass stellar and sub-stellar objects identified by the Two-Micron All Sky Survey (2MASS). CorMASS' efficiency and resolution also make it a versatile instrument for the spectral observation and classification of many other types of bright objects (K<14) including quasars, novae, and emission line objects.Comment: To be published in Feb 2001 PASP, 19 pages, 12 Figures, High Resolution file can be retrieved from ftp://iras2.tn.cornell.edu/pub/wilson/papers/cormass.ps.g

Assessment of left atrial volume before and after pulmonary thromboendarterectomy in chronic thromboembolic pulmonary hypertension.

BackgroundImpaired left ventricular diastolic filling is common in chronic thromboembolic pulmonary hypertension (CTEPH), and recent studies support left ventricular underfilling as a cause. To investigate this further, we assessed left atrial volume index (LAVI) in patients with CTEPH before and after pulmonary thromboendarterectomy (PTE).MethodsForty-eight consecutive CTEPH patients had pre- &amp; post-PTE echocardiograms and right heart catheterizations. Parameters included mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index, LAVI, &amp; mitral E/A ratio. Echocardiograms were performed 6 ± 3 days pre-PTE and 10 ± 4 days post-PTE. Regression analyses compared pre- and post-PTE LAVI with other parameters.ResultsPre-op LAVI (mean 19.0 ± 7 mL/m2) correlated significantly with pre-op PVR (R = -0.45, p = 0.001), mPAP (R = -0.28, p = 0.05) and cardiac index (R = 0.38, p = 0.006). Post-PTE, LAVI increased by 18% to 22.4 ± 7 mL/m2 (p = 0.003). This change correlated with change in PVR (765 to 311 dyne-s/cm5, p = 0.01), cardiac index (2.6 to 3.2 L/min/m2, p = 0.02), and E/A (.95 to 1.44, p = 0.002).ConclusionIn CTEPH, smaller LAVI is associated with lower cardiac output, higher mPAP, and higher PVR. LAVI increases by ~20% after PTE, and this change correlates with changes in PVR and mitral E/A. The rapid increase in LAVI supports the concept that left ventricular diastolic impairment and low E/A pre-PTE are due to left heart underfilling rather than inherent left ventricular diastolic dysfunction

Trigonometric Parallaxes of Central Stars of Planetary Nebulae

Trigonometric parallaxes of 16 nearby planetary nebulae are presented, including reduced errors for seven objects with previous initial results and results for six new objects. The median error in the parallax is 0.42 mas, and twelve nebulae have parallax errors less than 20 percent. The parallax for PHL932 is found here to be smaller than was measured by Hipparcos, and this peculiar object is discussed. Comparisons are made with other distance estimates. The distances determined from these parallaxes tend to be intermediate between some short distance estimates and other long estimates; they are somewhat smaller than estimated from spectra of the central stars. Proper motions and tangential velocities are presented. No astrometric perturbations from unresolved close companions are detected.Comment: 24 pages, includes 4 figures. Accepted for A

Planetary nebulae in the elliptical galaxy NGC 821: kinematics and distance determination

Using a slitless spectroscopy method with the 8.2 m Subaru telescope and its FOCAS Cassegrain spectrograph, we have increased the number of planetary nebula (PN) detections and PN velocity measurements in the flattened elliptical galaxy NGC 821. A comparison with the detections reported previously by the Planetary Nebula Spectrograph (PN.S) group indicates that we have confirmed most of their detections. The velocities measured by the two groups, using different telescopes, spectrographs and slitless techniques, are in good agreement. We have built a combined sample of 167 PNs and have confirmed the keplerian decline of the line-of-sight velocity dispersion reported previously. We also confirm misaligned rotation from the combined sample. A dark matter halo may exist around this galaxy, but it is not needed to keep the PN velocities below the local escape velocity as calculated from the visible mass. We have measured the m(5007) magnitudes of 145 PNs and produced a statistically complete sample of 40 PNs in NGC 821. The resulting PN luminosity function (PNLF) was used to estimate a distance modulus of 31.4 mag, equivalent to 19 Mpc. We also estimated the PN formation rate. NGC 821 becomes the most distant galaxy with a PNLF distance determination. The PNLF distance modulus is smaller than the surface brightness fluctuation (SBF) distance modulus by 0.4 mag. Our kinematic information permits to rule out the idea that a shorter PNLF distance could be produced by the contamination of the PNLF by background galaxies with emission lines redshifted into the on-band filter transmission curve.Comment: Accepted for publication in ApJ; 16 figure

Triplets of Quasars at high redshift I: Photometric data

We have conducted an optical and infrared imaging in the neighbourhoods of 4 triplets of quasars. R, z', J and Ks images were obtained with MOSAIC II and ISPI at Cerro Tololo Interamerican Observatory. Accurate relative photometry and astrometry were obtained from these images for subsequent use in deriving photometric redshifts. We analyzed the homogeneity and depth of the photometric catalog by comparing with results coming from the literature. The good agreement shows that our magnitudes are reliable to study large scale structure reaching limiting magnitudes of R = 24.5, z' = 22.5, J = 20.5 and Ks = 19.0. With this catalog we can study the neighbourhoods of the triplets of quasars searching for galaxy overdensities such as groups and galaxy clusters.Comment: The paper contains 12 figures and 3 table

The evolution of M 2-9 from 2000 to 2010

M 2-9, the Butterfly nebula, is an outstanding representative of extreme aspherical flows. It presents unique features such as a pair of high-velocity dusty polar blobs and a mirror-symmetric rotating pattern in the inner lobes. Imaging monitoring of the evolution of the nebula in the past decade is presented. We determine the proper motions of the dusty blobs, which infer a new distance estimate of 1.3+-0.2 kpc, a total nebular size of 0.8 pc, a speed of 147 km/s, and a kinematical age of 2500 yr. The corkscrew geometry of the inner rotating pattern is quantified. Different recombination timescales for different ions explain the observed surface brightness distribution. According to the images taken after 1999, the pattern rotates with a period of 92+-4 yr. On the other hand, the analysis of images taken between 1952 and 1977 measures a faster angular velocity. If the phenomenon were related to orbital motion, this would correspond to a modest orbital eccentricity (e=0.10+-0.05), and a slightly shorter period (86+-5 yr). New features have appeared after 2005 on the west side of the lobes and at the base of the pattern. The geometry and travelling times of the rotating pattern support our previous proposal that the phenomenon is produced by a collimated spray of high velocity particles (jet) from the central source, which excites the walls of the inner cavity of M 2-9, rather than by a ionizing photon beam. The speed of such a jet would be remarkable: between 11000 and 16000 km/s. The rotating-jet scenario may explain the formation and excitation of most of the features observed in the inner nebula, with no need for additional mechanisms, winds, or ionization sources. All properties point to a symbiotic-like interacting binary as the central source of M 2-9.Comment: Accepted for publication on Astronomy and Astrophysics (10 pages, 8 figures