Monitoring The HRC-S UV Rate: Observations of Vega
نویسندگان
چکیده
We present an interim report on Chandra HRC-S calibration observations of Vega, an Xray–dark and UV-bright star. The purpose of the observations is to monitor the UV response of the detector, and recently it has acquired further importance as a means to track the effects of increased radiation dosage on the UV/ion-shield of the detector. We find no conclusive evidence that leaving the HRC door open during radiation-zone passage is adversely affecting the UVIS. In order to spot any degradation early, we recommend continuing the higher frequency schedule of observations.
منابع مشابه
The Discovery of a Very Faint X-ray Transient in the Globular Cluster M15
We have identified an X-ray transient (hereafter M15 X-3) in the globular cluster M15 from an archival Chandra grating observation. M15 X-3 appears at an X-ray luminosity of 6 × 10 ergs s with a spectrum consistent with an absorbed power law of photon index 1.51±0.14. The object is identifiable in archival Chandra HRC-I observations with an X-ray luminosity of 2− 6× 10 ergs s and apparently sof...
متن کاملMortality reduction by heart rate characteristic monitoring in very low birth weight neonates: a randomized trial.
OBJECTIVE To test the hypothesis that heart rate characteristics (HRC) monitoring improves neonatal outcomes. STUDY DESIGN We conducted a two-group, parallel, individually randomized controlled clinical trial of 3003 very low birth weight infants in 9 neonatal intensive care units. In one group, HRC monitoring was displayed; in the other, it was masked. The primary outcome was number of days ...
متن کاملNew measures of heart-rate complexity: effect of chest trauma and hemorrhage.
BACKGROUND Traditional vital signs such as heart rate, blood pressure, and oxygen saturation are not ideal for timely and accurate assessment of physiologic status after trauma (TR) and hemorrhagic shock (HS). Analysis of the complex beat-to-beat variability present in the heart-rate time series has been proposed as a "new vital sign" in this setting. We determined the effect of chest TR and HS...
متن کاملA&a Manuscript No. Astronomy and Astrophysics Co in the Circumstellar Disks of Vega and Pictoris
Vega and Pictoris are the most prominent A stars surrounded by dust disks. However up to now CO radio observations have not revealed any gas in the circumstellar environment. We present thin hydrostatic equilibrium models for the disks around these stars using ATLAS9 photospheric models (Kurucz 1992) to determine the stellar UV ux and to derive the dust temperature from radiative equilibrium. D...
متن کاملObservations of M 31
As part of the Chandra GTO program we are monitoring and surveying M31 using the HRC and ACIS cameras. These observations have resolved the nuclear X-ray source into five separate sources, one of which is very soft and may (or may not!) be associated with the central super-massive black hole. In addition, the superb spatial resolution and low scattering of the Chandra telescope allows us to una...
متن کامل