Effective Temperature Of Uranus

NASA NGR 09-015-047, NGR 22-007-270, NGR 44-012-152Astronom

Strong UV and X-ray variability of the Narrow Line Seyfert 1 Galaxy WPVS 007 -- on the nature of the X-ray low state

We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS 007. The galaxy was monitored with Swift between October 2005 and July 2013, after it had undergone a dramatic drop in its X-ray flux earlier. For the first time, we are able to repeatedly detect this NLS1 in X-rays again. This increased number of detections in the last couple of years may suggest that the strong absorber that has been found in this AGN is starting to become leaky, and may eventually disappear. The X-ray spectra obtained for WPVS 007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4 x 10^23 cm^-2 with a covering fraction of 95%. WPVS 007 also displays one of the strongest UV variabilities seen in Narrow Line Seyfert 1s. The UV continuum variability anti-correlates with the optical/UV slope alpha-UV which suggests that the variability primarily may be due to reddening. The UV variability time scales are consistent with moving dust `clouds' located beyond the dust sublimation radius of approximately 20 ld. We present for the first time near infrared JHK data of WPVS 007, which reveal a rich emission-line spectrum. Recent optical spectroscopy does not indicate significant variability in the broad and FeII emission lines, implying that the ionizing continuum seen by those gas clouds has not significantly changed over the last decades. All X-ray and UV observations are consistent with a scenario in which an evolving Broad Absorption Line (BAL) flow obscures the continuum emission. As such, WPVS 007 is an important target for our understanding of BAL flows in low-mass active galactic nuclei (AGN).Comment: Accepted for publications in the Astronomical Journal; 29 pages, 10 Figures, 7 Table

Forming a Hypothesis

Provides pedagogical insight concerning the skill of hypothesizing The resource being annotated is: http://www.dlese.org/dds/catalog_DLESE-000-000-007-442.htm

Embrapa desenvolve programa de computador para avaliar risco de contaminação ambiental por agrotóxicos.

bitstream/item/40724/1/Embrapa-desenvolve-programa-de...-romulo.pdfSIDE 007/11A - Cultivar 22 mar. 2011; SIDE 007/11B - Safracheia 24 mar. 2011; SIDE 007/11C - Regional @ Toda Raça 22 mar. 2011; SIDE 007/11D - Panificação Brasileira 22 mar. 2011; SIDE 007/11E - Portal do Agronegócio 22 mar 2011; SIDE 007/11F - Inova Defesa 22 mar. 2011; SIDE 007/11G - Mato Grosso on-line 21 mar. 2011

Using Data in Undergraduate Science Classrooms

Provides pedagogical insight concerning the skill of using data The resource being annotated is: http://www.dlese.org/dds/catalog_DATA-CLASS-000-000-000-007.htm

Khine Swe, M. (Ed.) (2013) Critical analysis of science textbooks: evaluating instructional effectiveness [Kriticna analiza naravoslovnih ucbenikov: ocenjevanje ucinkovitosti poucevanja]. Dordrecht [etc.]: Springer. [Book review]

Book review of: Khine Swe, M. (Ed.) (2013) Critical analysis of science textbooks: evaluating instructional effectiveness [Kriticna analiza naravoslovnih ucbenikov: ocenjevanje ucinkovitosti poucevanja]. Dordrecht [etc.]: Springer. ISBN 978-94-007-4167-6

First detection of hard X-ray photons in the soft X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007: The X-ray photon distribution observed by Swift

We report on the first detection of hard X-ray photons (E>2.5 keV) in the X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007 which was the AGN with the softest X-ray spectrum during the ROSAT All-Sky Survey. The AGN is clearly detected at a level of about 2 x 10^{-17} W m^{-2} in the observed 0.3-10.0 keV band by Swift in a 50 ks observation in 2007 September. For the first time since the ROSAT All-Sky Survey observation in 1990 it was possible to derive an X-ray photon distribution by adding together all Swift observations that have been performed so far (85.5 ks in total). This photon distribution is consistent with an X-ray spectrum of an AGN with a partial covering absorber with a column density in the order of ~ 1 x 10^{23} cm^{-2} and a covering fraction of about 90%. A comparison with the 2002 Chandra data suggests that WPVS 007 has become brighter by a factor of about 4. The Swift data also suggest that the absorber which is causing the current low-state may have started to disappear. This disappearance is indicated by a significant change in the hardness ratio from a very soft X-ray state during the 2005 October to 2007 January observations to a rather hard X-ray state in the 2007 September observations. In the UV, WPVS 007 seems to become fainter by up to 0.5 mag over the last two years. The optical to X-ray spectral slope derived from the spectral energy distribution is alpha-ox=2.5 which classifies WPVS 007 as an X-ray weak AGN. After correcting for reddening and X-ray absorption, alpha-ox becomes 1.9 and the luminosity in the Big-Blue-Bump is log LBBB=37.7 [W], which translates into an Eddington ratio L/LEdd ~ 1.0.Comment: Accepted for publication in the Astronomical Journal, scheduled for December 2008, 8 pages, 3 figures, 3 table

Short lists with short programs in short time - a short proof

Bauwens, Mahklin, Vereshchagin and Zimand [ECCC TR13-007] and Teutsch [arxiv:1212.6104] have shown that given a string x it is possible to construct in polynomial time a list containing a short description of it. We simplify their technique and present a shorter proof of this result

The unblinking eye on the sky

From near-Earth asteroids to superluminous supernovae and counterparts to gravitational wave sources, the Zwicky Transient Facility will soon scan the night sky for transient phenomena.Comment: Author's version of "Mission Control" profile published in Nature Astronomy. 3 pages, 1 figure. https://www.nature.com/articles/s41550-017-007