423 research outputs found
RX J1643.7+3402: a new bright cataclysmic variable
We report the discovery of a new bright (V12.6) cataclysmic variable star identified with the ROSAT X-ray source RX J1643.7+3402. Spectroscopic and photometric observations show it to be a novalike variable sharing some of the characteristics of the SW Sex sub-class of novalike CVs. The spectroscopic period may be either 2\fh575 or 2\fh885, within the period "gap." A photometric modulation with a probable period of 2\fh595 and an amplitude of 0.1 mag in V is present on most nights and could be either a "positive" or a "negative" superhump modulation (depending on the exact spectroscopic period), indicating the presence of a precessing accretion disk in this system. Rapid variations of 0.1 to 0.2 mag amplitude in V repeat with a time scale of 15 min
Molecular gas in QSO host galaxies
We present the results of a survey for CO line emission from a sample of
nearby QSO hosts taken from the Hamburg/ESO survey (HES) and the Veron-Cetty
and Veron quasar catalogue. From a total of 39 observed sources we clearly
detected 5 objects with >10sigma signals (HE 0108-4743, HE 0224-2834,
J035818.7-612407, HE 1029-1831, HE 2211-3903). Further 6 sources show marginal
detections on the 2sigma level.Comment: 4 pages, 1 figure, submitted to "QSO Hosts: Evolution and
Environment", P.D. Barthel, D.B. Sanders, eds., August 2005, Leiden
University (The Netherlands), New Astr. Re
On Uniqueness of Boundary Blow-up Solutions of a Class of Nonlinear Elliptic Equations
We study boundary blow-up solutions of semilinear elliptic equations
with , or with , where is a second order
elliptic operator with measurable coefficients. Several uniqueness theorems and
an existence theorem are obtained.Comment: To appear in Comm. Partial Differential Equations; 10 page
How would farmers in the French Alps adapt their systems to different drought and socio-economic context scenarios?
International audienceThe French Alps are considered as an area that is particularly vulnerable to climate change. Several droughts have already occurred since 2003. In order to assess the ability of farming systems to adapt to future drought events, we developed prospective scenarios combining different climatic and socio-economic contexts. Four scenarios were defined based on (i) prospective studies conducted at national and international levels, and (ii) a participatory approach with various stakeholders to transcribe these scenarios at a local level. Farmers and shepherds in the Vercors and Oisans massifs were surveyed in order to understand how they had reacted to previous droughts, and how they would plan to react to our scenarios. Results show first that the farmers would strive to continue their activity in each scenario, taking advantage of the flexibility of their farming systems, as in previous years. However, in the most pessimistic climatic scenario, they would also decrease the size of their herds. Depending on the socio-economic hypothesis, they would adopt farm structural changes (farm processing activities, direct selling, etc.), or look for part-time non-agricultural jobs. Three types of strategies were identified, depending on the farmers' objectives and adjustments. Finally, public policies to accompany these changes are considered
Recommended from our members
Patent Litigation in Europe
We compare patent litigation cases across four European jurisdictionsâGermany, the UK (England and Wales), France, The Netherlandsâusing case-level data gathered from cases filed in the four jurisdictions during the period 2000â2008. Overall, we find substantial differences across jurisdictions in terms of caseloadsânotably, courts in Germany hear by far the largest number of cases, not only in absolute terms, but also when taking macro-economic indicators into accountâand we further find important cross-country variances in terms of case outcomes. Moreover, we show empirically that a considerable number of patents are litigated across multiple European jurisdictions; and further, that in the majority of these cases divergent case outcomes are reached across the different jurisdictions, suggesting that the long-suspected problem of inconsistency of decision-making in European patent litigation is in fact real. Finally, we note that the coming into force of the Unified Patent Court in Europe may, in the long term, help to alleviate this inconsistency problem
Diagnostics of the structure of AGN's broad line regions with reverberation mapping data: confirmation of the two-component broad line region model
We re-examine the ten Reverberation Mapping (RM) sources with public data
based on the two-component model of the Broad Line Region (BLR). In fitting
their broad H-beta lines, six of them only need one Gaussian component, one of
them has a double-peak profile, one has an irregular profile, and only two of
them need two components, i.e., a Very Broad Gaussian Component (VBGC) and an
Inter-Mediate Gaussian Component (IMGC). The Gaussian components are assumed to
come from two distinct regions in the two-component model; they are Very Broad
Line Region (VBLR) and Inter-Mediate Line region (IMLR). The two sources with a
two-component profile are Mrk 509 and NGC 4051. The time lags of the two
components of both sources satisfy ,
where and are the lags of the two components while
and represent the mean gas velocities of the two regions,
supporting the two-component model of the BLR of Active Galactic Nuclei (AGN).
The fact that most of these ten sources only have the VBGC confirms the
assumption that RM mainly measures the radius of the VBLR; consequently, the
radius obtained from the R-L relationship mainly represent the radius of VBLR.
Moreover, NGC 4051, with a lag of about 5 days in the one component model, is
an outlier on the R-L relationship as shown in Kaspi et al. (2005); however
this problem disappears in our two-component model with lags of about 2 and 6
days for the VBGC and IMGC, respectively.Comment: 7 pages, 5 figures. Accepted for publication in the Special Issue of
Science in China (G) "Astrophysics of Black holes and Related Compact
Objects
- âŠ