Mergers and starbursts at large redshifts - The case of 3C 368

We report the results of a multiwavelength study of the high-redshift radio galaxy 3C 368, which is observed at a lookback time of about two-thirds of the present galaxian age. This galaxy has optical and spectroscopic properties that are perhaps typical for the powerful 3CR galaxies at large redshifts (z > 1 ), though it is probably more luminous than the most, both in continuum and [O II]. Its resolved, multicomponent morphology of the starlight continuum and the [O II] λ 3727 emission-line gas, and the properties of the ionized-gas velocity field, are suggestive of a strong and highly dissipative merger. There is a good positional and morphological coincidence between the line emission and the optical continuum. The proposed merger is probably enhancing the star formation over the whole galaxy (as evidenced by the large luminosity and the blue colors of the optical continuum), and may be the primary source of the fuel for, or even the trigger of, the strong radio emission from the system. The morphological and spectroscopic similarities with other 3CR galaxies at z > 1 suggest that spectacular merging was a common process in such systems at early epochs. The mergers may be identified with the process of transformation of (large?) E galaxies into cD’s, and the epoch of such “secondary” formation of gE/cD galaxies may be signalled by the appearance of powerful radio sources at z ~ 1-2. The galaxy evolution models with a continuing star formation, suggested by the colors and magnitudes of high-redshift 3CR galaxies, may be understood in terms of a declining sequence of starbursts, stimulated by gas-rich mergers. There are also some indications of an ongoing interaction between the radio lobes and the ambient gas: both radio lobes show a prominent Faraday rotation and depolarization, probably caused by the intervening plasma along the line of sight. There is also a reasonable positional coincidence between the southern radio lobe and the emission-line gas. However, the evidence for an interaction between the radio plasma and the gas in the host galaxy is neither clear nor unambiguous

Outer jet X-ray and radio emission in R Aquarii: 1999.8 to 2004.0

Chandra and VLA observations of the symbiotic star R Aqr in 2004 reveal significant changes over the three to four year interval between these observations and previous observations taken with the VLA in 1999 and with Chandra in 2000. This paper reports on the evolution of the outer thermal X-ray lobe-jets and radio jets. The emission from the outer X-ray lobe-jets lies farther away from the central binary than the outer radio jets, and comes from material interpreted as being shock heated to ~10^6 K, a likely result of collision between high speed material ejected from the central binary and regions of enhanced gas density. Between 2000 and 2004, the Northeast (NE) outer X-ray lobe-jet moved out away from the central binary, with an apparent projected motion of ~580 km s^-1. The Southwest (SW) outer X-ray lobe-jet almost disappeared between 2000 and 2004, presumably due to adiabatic expansion and cooling. The NE radio bright spot also moved away from the central binary between 2000 and 2004, but with a smaller apparent velocity than of the NE X-ray bright spot. The SW outer lobe-jet was not detected in the radio in either 1999 or 2004. The density and mass of the X-ray emitting material is estimated. Cooling times, shock speeds, pressure and confinement are discussed.Comment: 23 pages, 8 figure

The Operational Land Imager: Spectral Uniformity

No abstract availabl

Mergers and starbursts at large redshifts - The case of 3C 368

We report the results of a multiwavelength study of the high-redshift radio galaxy 3C 368, which is observed at a lookback time of about two-thirds of the present galaxian age. This galaxy has optical and spectroscopic properties that are perhaps typical for the powerful 3CR galaxies at large redshifts (z > 1 ), though it is probably more luminous than the most, both in continuum and [O II]. Its resolved, multicomponent morphology of the starlight continuum and the [O II] λ 3727 emission-line gas, and the properties of the ionized-gas velocity field, are suggestive of a strong and highly dissipative merger. There is a good positional and morphological coincidence between the line emission and the optical continuum. The proposed merger is probably enhancing the star formation over the whole galaxy (as evidenced by the large luminosity and the blue colors of the optical continuum), and may be the primary source of the fuel for, or even the trigger of, the strong radio emission from the system. The morphological and spectroscopic similarities with other 3CR galaxies at z > 1 suggest that spectacular merging was a common process in such systems at early epochs. The mergers may be identified with the process of transformation of (large?) E galaxies into cD’s, and the epoch of such “secondary” formation of gE/cD galaxies may be signalled by the appearance of powerful radio sources at z ~ 1-2. The galaxy evolution models with a continuing star formation, suggested by the colors and magnitudes of high-redshift 3CR galaxies, may be understood in terms of a declining sequence of starbursts, stimulated by gas-rich mergers. There are also some indications of an ongoing interaction between the radio lobes and the ambient gas: both radio lobes show a prominent Faraday rotation and depolarization, probably caused by the intervening plasma along the line of sight. There is also a reasonable positional coincidence between the southern radio lobe and the emission-line gas. However, the evidence for an interaction between the radio plasma and the gas in the host galaxy is neither clear nor unambiguous

Preliminary Results on HAT-P-4, TrES-3, XO-2, and GJ 436 from the NASA EPOXI Mission

EPOXI (EPOCh + DIXI) is a NASA Discovery Program Mission of Opportunity using the Deep Impact flyby spacecraft. The EPOCh (Extrasolar Planet Observation and Characterization) Science Investigation will gather photometric time series of known transiting exoplanet systems from January through August 2008. Here we describe the steps in the photometric extraction of the time series and present preliminary results of the first four EPOCh targets.Comment: 4 pages, 2 figures. To appear in the Proceedings of the 253rd IAU Symposium: "Transiting Planets", May 2008, Cambridge, M

A Tamarisk Habitat Suitability Map for the Continental US

This paper presents a national-scale map of habitat suitability for a high-priority invasive species, Tamarisk (Tamarisk spp., salt cedar). We successfully integrate satellite data and tens of thousands of field sampling points through logistic regression modeling to create a habitat suitability map that is 90% accurate. This interagency effort uses field data collected and coordinated through the US Geological Survey and nation-wide environmental data layers derived from NASA s MODerate Resolution Imaging Spectroradiometer (MODIS). We demonstrate the utilization of the map by ranking the lower 48 US states (and the District of Columbia) based upon their absolute, as well as proportional, areas of highly likely and moderately likely habitat for Tamarisk. The interagency effort and modeling approach presented here could be applied to map other harmful species in the US and globally

Discovery of Rapid Hard X-ray Variability and New Jet Activity in the Symbiotic Binary R Aqr

Two Chandra observations of the R Aqr symbiotic binary system taken 3.3 years apart show dramatic changes in the X-ray morphology and spectral characteristics in the inner 500 AU of this system. The morphology of the soft X-ray emission has evolved from a nearly circular region centered on the binary system to an hourglass shape that indicates the formation of a new southwest jet. Synchrotron radiation from the new jet in contemporaneous VLA radio spectra implies the physical conditions in the early stages of jet development are different from those in the more extended outer thermal jets known to exist for decades in this system. The central binary source has two X-ray spectral components in each of the two epochs, a soft component and a highly absorbed hard component characterized by T ~ 10^8 K if fit with a thermal plasma model. The spectrum hardened considerably between 2000.7 and 2004.0, primarily due to increased flux above 5 keV, suggesting a change in the accretion activity of the white dwarf on a timescale of a few years or less. Point-source Fe K emission is detected at the position of the central binary system in both observations. While the earlier observation shows evidence of only a single emission peak near Fe K alpha at 6.4 keV, the later observation shows a more complex emission structure between 6 and 7 keV. Finally, we have discovered a modulation in the hard X-ray flux with a period of 1734 s at a 95% confidence level in the 2004 observation only. The modulation potentially arises from standing shocks in an accretion column and we have explored the possibility that the white dwarf in R Aqr is analogous to the magnetic white dwarfs in Intermediate Polar.Comment: 31 pages, 14 figures, 1 table To be published in ApJ, expected April 10 issue. AAS LaTex styl

Sound archaeology: terminology, Palaeolithic cave art and the soundscape

This article is focused on the ways that terminology describing the study of music and sound within archaeology has changed over time, and how this reflects developing methodologies, exploring the expectations and issues raised by the use of differing kinds of language to define and describe such work. It begins with a discussion of music archaeology, addressing the problems of using the term ‘music’ in an archaeological context. It continues with an examination of archaeoacoustics and acoustics, and an emphasis on sound rather than music. This leads on to a study of sound archaeology and soundscapes, pointing out that it is important to consider the complete acoustic ecology of an archaeological site, in order to identify its affordances, those possibilities offered by invariant acoustic properties. Using a case study from northern Spain, the paper suggests that all of these methodological approaches have merit, and that a project benefits from their integration

Developmental differences in holistic interference of facial part recognition.

Research has shown that adults' recognition of a facial part can be disrupted if the part is learnt without a face context but tested in a whole face. This has been interpreted as the holistic interference effect. The present study investigated whether children of 6- and 9-10-year-olds would show a similar effect. Participants were asked to judge whether a probe part was the same as or different from a test part whereby the part was presented either in isolation or in a whole face. The results showed that while all the groups were susceptible to a holistic interference, the youngest group was most severely affected. Contrary to the view that piecemeal processing precedes holistic processing in the cognitive development, our findings demonstrate that holistic processing is already present at 6 years of age. It is the ability to inhibit the influence of holistic information on piecemeal processing that seems to require a longer period of development into at an older and adult age