In early mid-infrared observations (c 1970) two prominent dust emission features were discovered. ... Soon after the discovery of the silicate features another feature at about 11.3 microns was discovered in the spectra of some carbon stars, not as wide or as strong as the silicate features but still thought to be due to a solid material. ... less common features: extreme carbon stars, the AlO/silicate complex, the "unidentified infrared" features, unusual silicate features . ...

Next: Analysis in the Up: MIDAS utilities for Previous: Fourier analysis . For the detection of smooth signals, e.g. sinusoids, use either SCARGLE/TSA or AOV/TSA with bins. ... SCARGLE/TSA -- . Scargle sine model: This command computes Scargle's (1982) periodogram for unevenly spaced observations x . ... In this way, the command can be used to perform a CLEAN-like analysis manually by removing individual oscillations one by one in the time domain (see Roberts et al. ... AOV/TSA -- . ...

... A typical spectrum (such as Figure 1) shows the classic triple-peaked spectrum, which is associated with masers located in a circumnuclear disk (e.g. NGC 4258, Nakai et al., ... The Circinus galaxy megamasers are known to be variable on timescales of weeks and months with individual maser features having a lifetime of around one year. ... Most of the masers observed showed some degree of variability over an hour while one feature displayed a doubling of its flux density over about 10 minutes. ...

... Maps of 21cm emission are dominated by warm H i, and most observations of H i absorption against continuum sources are limited to discrete points. ... Current Results At right are maps of H i emission, HISA, and 12 CO emission in the eastern 25% of the survey, given as projections along the velocity (Figure 1) and latitude (Figure 2) axes. ... 2000, A. J., submitted Figure 1: H i Survey Map (`; b): H i 21cm brightness integrated over all velocity channels; white is bright and black is faint. ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

... A new IRAF task has been developed that automatically identifies linear (line-like) features in an image or set of images. ... In order to automatically detect linear features, the first step is to select pixels in the image (Fig. 1 , left panel) that fall within a given data value range. ... Another aspect of extended linear features is that the image space pixels that describe them are in some way adjacent to one another and have a minimum and maximum length. ...

... If finddead =Y, embadpixfind looks for too dark pixels, rows and columns too. ... The maxratio parameter avoids detecting 'grey' pixels, rows or columns on observations with high statistics. Whatever findbright and finddead , dark and bright columns and rows are always searched for together in order of decreasing significance (either positive or negative). This avoids finding spurious bright columns/rows next to very dark ones, and vice-versa. ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

... Visible Distribution of Galaxies. ... Features of Elliptical, Lens-Shaped, Spiral and Irregular Galaxies. Galaxies with Bar. ... Distribution of Surface Brightness of Surface and Spiral Galaxies. ... Color Characteristics of Galaxies. ... Methods of Galaxies' Mass Determination. ... Hidden Mass of Spiral Galaxies. ... Features of Dark Matter Distribution in E and SO Galaxies. ... The Whole Number of Galaxies and Their Density by the Results of Observation on the 'Hubble' Space Telescope. ...

. True Color Image Gallery: Galactic SNR | Magellanic Cloud SNR . Images show regions used to extract spectra . Regions with red strikes are excluded . Background was subtracted from a region around or close to the SNR. Back to J0051.1-7321 Index . Chandra Supernova Remnant Catalog . Main Page | Galactic SNR | Magellanic Cloud SNR . True Color Image Gallery: Galactic SNR | Magellanic Cloud SNR .

Next: Imaging Polarimetry with NICMOS Up: NICMOS Data Calibration and Previous: The Photometric Performance of . ... NICMOSlook and Calnic C . ... Extracting spectra from a large number of NICMOS grism images requires a convenient interactive tool which allows a user to manipulate direct/grism image pairs. ... NICMOSlook and Calnic-C are two programs that were designed to take advantage of the fact that the NICMOS grism mode typically consists of taking both a direct and a grism image. ...

The galactic binary GW noisewill be modulated by the LISA orbital motion, whereas the extragalactic one will not. If the latter is comparable with galactic values at some galactic latitudes, it can impede detection by LISA of some inter­ esting relic cosmological GW backgrounds, and specific statistical features of the relic GW should be used to separate them against the noise from astrophysical sources. ...

Next: Feature enhancement: local Up: No Title Previous: Feature enhancement: filtering . ... As a result, a common magnitude scale (contour lines on the maps above, or color scale on Fig.1) will poorly display the short-duration events in a signal. Normalizing each line of the map (fixed duration) so it has unit variance (in effect dividing the energy map by the mean energy spectrum) at each duration restores more details of small-scale activity (Fig. ...

Clay minerals show green in this false-color image made with two of the Mars Reconnaissance Orbiter's instruments. The region is Nili Fossae, and was shot on October 4, 2006. Features as small as 60 feet (18 meters) are resolved in the multicolor CRISM image, which reveals mineralogy; the HiRISE background topography, taken in 3 colors, shows features as small as 1 foot (30 centimeters) across. ... Reddish areas indicate dunes of sand rich in the mineral olivine. ...

... Galaxies 99 Cosmic background with model of cloudy interstellar medium Yu. ... Figure 1: Averaged spectrum of the cosmic background I f in frequency range 0.25 200 MHz for the Galactic poles. ... First interpretation of the cosmic noise background spectrum at broad band frequency range 0.25 200 MHz with a model of the cloudy interstellar medium ISM is presented here. ... Synthesized background spectra I f for regions of the Galactic poles at the frequency range 0.25 200 MHz is presented in Fig. ...

... Primordial theory review : Dick Bond . Defects and the CMB review : Andy Albrecht . ... Gravitational wave contribution to CMB anisotropies : V.B. Lukash and E.V. Mikheeva . C_l from cosmic strings : Lloyd Knox . Some aspects of CMB anisotropies induced from topological defects : Mairi Sakellariadou . ... CMB anisotropies from scaling sources : Ruth Durrer . ... SZ observations I : Sarah Church . ... Holes in the microwave sky? ... Detecting cosmic strings in the CMB : James Robinson . ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2014 October 15 . Mysterious Changing feature on Titan . Image Credit: Cassini Radar Mapper , Cornell , JPL , ESA , NASA . Explanation: What is that changing object in a cold hydrocarbon sea of Titan? ... Subsequent observations in 2014 found the object remained -- but had changed! ... About APOD | ... A service of: ASD at NASA / GSFC . ...

... Mystery Feature Now Disappears in Titan Lake . ... Credit Copyright: Cassini Radar Mapper , Cornell , JPL , ESA , NASA Explanation: What is that changing object in a cold hydrocarbon sea of Titan? ... When imaging the flat -- and hence radar dark -- surface of the methane and ethane lake called Ligeia Mare , an object appeared in 2013 July just was not there in 2007. ... The featured false-color image shows how the 20-km long object has come, changed, and gone. ... Publications with keywords: Titan ...

Next: Radial velocity of the Up: Optical spectrum of IRAS04296 Previous: Observations and spectra reduction . ... However, molecular emission features are only very rarely observed in the optical spectra of PPNe. ... On the other hand, it is well known that cometary nuclei spectra show prominent Swan band emission. In both spectra of IRAS04296 we have discovered strong emission in the (0;0) and (0;1) bands of the Swan system of the molecule. ... Now consider the case of IRAS04296. ...

... Copyrightї1997 Bob Yen (byen@ix.netcom.com) (http://www.comet-track.com/hb/hb.html) . ... Information on Comet Hale-Bopp for the Non-Astronomer Hale-Bopp rotates about twice a day (3/14/97) . ... The Comet Observation Home Page was been selected to receive the Griffith Observatory Star Award for the week of February 2 - 8, 1997 for excellence in promoting astronomy to the public through the World Wide Web. ... Typically, about 1,000 individual users/computers access this page every day. ...