Observations

Observations on qualia, death, free will, why there is something rather than nothing, and the Star Trek vs. the Star Wars debate

Observations of Plasma Upflow in a Warm Loop with Hinode/EIS

A complete understanding of Doppler shift in active region loops can help probe the basic physical mechanism involved into the heating of those loops. Here we present observations of upflows in coronal loops detected in a range of temperature temperatures (log T=5.8 - 6.2). The loop was not discernible above these temperatures. The speed of upflow was strongest at the footpoint and decreased with height. The upflow speed at the footpoint was about 20 km/s in Fe VIII which decreased with temperature being about 13 km/s in Fe X, about 8 km/s in Fe XII and about 4 km/s in FeXIII. To the best of our knowledge this is the first observation providing evidence of upflow of plasma in coronal loop structures at these temperatures. We interpret these observations as evidence of chromospheric evaporation in quasi-static coronal loops.Comment: 14 pages, 5 figures, Accepted for Publication in The Astrophysical Journal Letter

Observations of Exoplanet Atmospheres

Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics & circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly-imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.Comment: Accepted for publication. 18pp, 10 figures. v3: fixed more reference

Learning from compressed observations

The problem of statistical learning is to construct a predictor of a random variable $Y$ as a function of a related random variable $X$ on the basis of an i.i.d. training sample from the joint distribution of $(X,Y)$. Allowable predictors are drawn from some specified class, and the goal is to approach asymptotically the performance (expected loss) of the best predictor in the class. We consider the setting in which one has perfect observation of the $X$-part of the sample, while the $Y$-part has to be communicated at some finite bit rate. The encoding of the $Y$-values is allowed to depend on the $X$-values. Under suitable regularity conditions on the admissible predictors, the underlying family of probability distributions and the loss function, we give an information-theoretic characterization of achievable predictor performance in terms of conditional distortion-rate functions. The ideas are illustrated on the example of nonparametric regression in Gaussian noise.Comment: 6 pages; submitted to the 2007 IEEE Information Theory Workshop (ITW 2007

ASCA Observations of NLS1s

The study of NLS1s using ASCA has many advantages. A representative sample can be studied; to date, observations of more than 30 NLS1s have been made. ASCA observations are conducted contiguously, so their X-ray variability properties can be studied systematically. ASCA detectors have a broad band pass and moderate energy resolution, properties which allow their complex X-ray spectrum to be deconvolved. ASCA observations have revealed that a soft excess extending up to 1 keV is frequently found in the X-ray spectra from NLS1s. The hard X-ray photon index has been shown to be systematically steeper than in Seyfert 1 galaxies with broad optical lines. NLS1s also exhibit larger amplitude variability than broad-line Seyferts of similar hard X-ray luminosity. On occasion, features in the soft X-ray band have been detected that appear to be specific to NLS1s; ionized iron lines have also been observed. These results have been fundamental for building our current picture of the X-ray emission from NLS1s. Many of the properties can be explained if the specific accretion rate is larger in NLS1s than in Seyfert 1 galaxies with broad optical lines. NLS1s may exemplify an extreme state of an intrinsic physical parameter and therefore their study may lead to an enhanced understanding of AGN in general. This proceedings contribution has two parts. First I describe and discuss some of the results obtained from a study of the X-ray variability in NLS1s using ASCA data (Leighly 1999ab). Then, I discuss the results from our HST observations of NLS1s that were first presented during this meeting (Leighly & Halpern 2000).Comment: Invited talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

Multiwavelength observations of blazars

The INTEGRAL mission has played a major role in blazar science, thanks to its sensitive coverage of a spectral region (3-100 keV) that is critical for this type of sources, to its flexibility of scheduling and to the large field of view of its cameras. A number of flat-spectrum radio quasars (up to z ~ 3) and BL Lac objects were observed by INTEGRAL together with facilities at all wavelengths. These results have advanced our knowledge of blazars from a physical and cosmological point of view. This paper reviews some of these outcomes, with particular reference to the INTEGRAL program for blazars in outburst as targets of opportunity, with a perspective into a future of multi-messenger astronomyComment: 7 pages, 1 figure, invited talk at the 11th INTEGRAL Conference "Gamma-Ray Astrophysics in Multi-Wavelength Perspective", Amsterdam, 10-14 October 2016. To be published in the Conf. Proceeding

DSN observations of Titan

When using Deep Space Station (DSS)-14 in a monostatic configuration, radar observations of Titan show that Titan is a diffuse reflector with a relative radar cross section of 0.14 +/- 0.03. No hot spots were observed

Special observations

The wind or temperature profiler is a new special observation device designed to supplement traditional atmospheric measurement and provide more accurate middle-range forecasts, including aviation and space applications. Radar is most useful in the short, nowcast time frame. Satellites and surface observations are also most useful for short-range forecasts but have less impact on the longer range. The radiosonde network, on the other hand, only starts to be very important after about six hours and has greatest impact at lead times of 12 hours or more. In the wind profiler, wind is measured by using clear-air Doppler radar principles, Two fixed beams, pointing 15 deg to the north and 15 deg to the east, sense the Doppler shift. The resulting wind vectors are then rotated to the horizontal and combined to give total wind. The temperature profiler measures temperature and humidity by using passive radiometers. Development on the profiler is 95 percent complete, and on the temperature profiler 75 percent complete