24 results match your criteria: "Infrared Processing and Analysis Center[Affiliation]"

Small bodies are capable of delivering essential prerequisites for the development of life, such as volatiles and organics, to the terrestrial planets. For example, empirical evidence suggests that water was delivered to the Earth by hydrated planetesimals from distant regions of the Solar System. Recently, several morphologically inactive near-Earth objects were reported to experience significant nongravitational accelerations inconsistent with radiation-based effects, and possibly explained by volatile-driven outgassing.

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Our knowledge of galaxy formation and evolution has incredibly progressed through multi-wavelength observational constraints of the interstellar medium (ISM) of galaxies at all cosmic epochs. However, little is known about the physical properties of the more diffuse and lower surface brightness reservoir of gas and dust that extends beyond ISM scales and fills dark matter haloes of galaxies up to their virial radii, the circumgalactic medium (CGM). New theoretical studies increasingly stress the relevance of the latter for understanding the feedback and feeding mechanisms that shape galaxies across cosmic times, whose cumulative effects leave clear imprints into the CGM.

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A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk.

Science

March 2024

Key Laboratory of Crust-Mantle Materials and Environment, Chinese Academy of Science, University of Science and Technology of China, Anhui 230026, China.

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula.

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In recent years, certain luminous extragalactic optical transients have been observed to last only a few days. Their short observed duration implies a different powering mechanism from the most common luminous extragalactic transients (supernovae), whose timescale is weeks. Some short-duration transients, most notably AT2018cow (ref.

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In the first billion years after the Big Bang, sources of ultraviolet (UV) photons are believed to have ionized intergalactic hydrogen, rendering the Universe transparent to UV radiation. Galaxies brighter than the characteristic luminosity L* (refs. ) do not provide enough ionizing photons to drive this cosmic reionization.

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Type Ia supernovae (SNe Ia) are thermonuclear explosions of degenerate white dwarf stars destabilized by mass accretion from a companion star, but the nature of their progenitors remains poorly understood. A way to discriminate between progenitor systems is through radio observations; a non-degenerate companion star is expected to lose material through winds or binary interaction before explosion, and the supernova ejecta crashing into this nearby circumstellar material should result in radio synchrotron emission. However, despite extensive efforts, no type Ia supernova (SN Ia) has ever been detected at radio wavelengths, which suggests a clean environment and a companion star that is itself a degenerate white dwarf star.

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Article Synopsis
  • Photochemistry plays a critical role in regulating the composition and stability of planetary atmospheres, but clear photochemical products have not been detected in exoplanets until recently.* -
  • The James Webb Space Telescope (JWST) detected sulfur dioxide (SO) in the atmosphere of the exoplanet WASP-39b, suggesting photochemical processes create SO in this gas giant's atmosphere.* -
  • The presence of SO, linked to the oxidation of hydrogen sulfide, indicates WASP-39b has high metallicity (about 10 times that of the sun), and its spectral features could help understand more about similar exoplanets.*
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Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures of planetary systems. However, few planets have been detected in blind surveys with direct imaging. Using astrometry from the Gaia and Hipparcos spacecraft, we identified dynamical evidence for a gas giant planet around the nearby star HIP 99770.

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The Saturn-mass exoplanet WASP-39b has been the subject of extensive efforts to determine its atmospheric properties using transmission spectroscopy. However, these efforts have been hampered by modelling degeneracies between composition and cloud properties that are caused by limited data quality. Here we present the transmission spectrum of WASP-39b obtained using the Single-Object Slitless Spectroscopy (SOSS) mode of the Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument on the JWST.

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Ultrashort-period (USP) exoplanets have orbital periods shorter than 1 day. Precise masses and radii of USP exoplanets could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the USP planet GJ 367b using high-precision photometry and radial velocity observations.

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SIFTING FOR SAPPHIRES: SYSTEMATIC SELECTION OF TIDAL DISRUPTION EVENTS IN iPTF.

Astrophys J Suppl Ser

October 2018

Oskar Klein Centre, Department of Physics, Stockholm University, SE 106 91 Stockholm, Sweden.

We present results from a systematic selection of tidal disruption events (TDEs) in a wide-area (4800 deg), + band, Intermediate Palomar Transient Factory (iPTF) experiment. Our selection targets typical optically-selected TDEs: bright (>60% flux increase) and blue transients residing in the center of red galaxies. Using photometric selection criteria to down-select from a total of 493 nuclear transients to a sample of 26 sources, we then use follow-up UV imaging with the Neil Gehrels Swift Telescope, ground-based optical spectroscopy, and light curve fitting to classify them as 14 Type Ia supernovae (SNe Ia), 9 highly variable active galactic nuclei (AGNs), 2 confirmed TDEs, and 1 potential core-collapse supernova.

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Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.

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Merging neutron stars offer an excellent laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of an electromagnetic counterpart (EM170817) with gravitational waves (GW170817) detected from merging neutron stars. By synthesizing a panchromatic data set, we demonstrate that merging neutron stars are a long-sought production site forging heavy elements by r-process nucleosynthesis.

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Zones, spots, and planetary-scale waves beating in brown dwarf atmospheres.

Science

August 2017

Infrared Processing and Analysis Center, MS 314-5, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125, USA.

Brown dwarfs are massive analogs of extrasolar giant planets and may host types of atmospheric circulation not seen in the solar system. We analyzed a long-term Spitzer Space Telescope infrared monitoring campaign of brown dwarfs to constrain cloud cover variations over a total of 192 rotations. The infrared brightness evolution is dominated by beat patterns caused by planetary-scale wave pairs and by a small number of bright spots.

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We report the discovery of a multiply imaged, gravitationally lensed type Ia supernova, iPTF16geu (SN 2016geu), at redshift = 0.409. This phenomenon was identified because the light from the stellar explosion was magnified more than 50 times by the curvature of space around matter in an intervening galaxy.

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Galaxies at redshifts 5 to 6 with systematically low dust content and high [C II] emission.

Nature

June 2015

1] Infrared Processing and Analysis Center (IPAC), 1200 East California Boulevard, Pasadena, California 91125, USA [2] California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.

The rest-frame ultraviolet properties of galaxies during the first three billion years of cosmic time (redshift z > 4) indicate a rapid evolution in the dust obscuration of such galaxies. This evolution implies a change in the average properties of the interstellar medium, but the measurements are systematically uncertain owing to untested assumptions and the inability to detect heavily obscured regions of the galaxies. Previous attempts to measure the interstellar medium directly in normal galaxies at these redshifts have failed for a number of reasons, with two notable exceptions.

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Saturn's faint outermost ring, discovered in 2009 (ref. 1), is probably formed by particles ejected from the distant moon Phoebe. The ring was detected between distances of 128 and 207 Saturn radii (RS = 60,330 kilometres) from the planet, with a full vertical extent of 40RS, making it well over ten times larger than Saturn's hitherto largest known ring, the E ring.

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Joint analysis of BICEP2/keck array and Planck Data.

Phys Rev Lett

March 2015

Department of Physics, University of California, Santa Barbara, California, USA.

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400  deg^{2} patch of sky centered on RA 0 h, Dec. -57.

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Inefficient star formation in extremely metal poor galaxies.

Nature

October 2014

1] School of Astronomy and Space Science, Nanjing University, Nanjing 210093, China [2] Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093, China.

The first galaxies contain stars born out of gas with few or no 'metals' (that is, elements heavier than helium). The lack of metals is expected to inhibit efficient gas cooling and star formation, but this effect has yet to be observed in galaxies with an oxygen abundance (relative to hydrogen) below a tenth of that of the Sun. Extremely metal poor nearby galaxies may be our best local laboratories for studying in detail the conditions that prevailed in low metallicity galaxies at early epochs.

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The current model of transferring data from data centres to desktops for analysis will soon be rendered impractical by the accelerating growth in the volume of science datasets. Processing will instead often take place on high-performance servers co-located with data. Evaluations of how new technologies such as cloud computing would support such a new distributed computing model are urgently needed.

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This paper presents a case study of an approach to sustainable software architecture that has been successfully applied over a period of 10 years to astronomy software services at the NASA Infrared Processing and Analysis Center (IPAC), Caltech (http://www.ipac.caltech.

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Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs. Visible/near-infrared and thermal-infrared synthetic spectra of these planets were generated to determine which biosignature gases might be observed by a future, space-based telescope. Our star sample included two observed active M dwarfs-AD Leo and GJ 643-and three quiescent model stars.

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A search for companions to nearby brown dwarfs: the binary DENIS-P J1228.2-1547.

Science

March 1999

Department of Astronomy, University of California, Berkeley, CA 94720, USA. Jet Propulsion Laboratory/Infrared Processing and Analysis Center, Mail Code 100-22, Pasadena, CA 91125, USA.

Hubble Space Telescope imaging observations of two nearby brown dwarfs, DENIS-P J1228.2-1547 and Kelu 1, made with the near-infrared camera and multiobject spectrometer (NICMOS), show that the DENIS object is resolved into two components of nearly equal brightness with a projected separation of 0.275 arc second (5 astronomical units for a distance of 18 parsecs).

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