... It is reasonable to expect a priori that the evolution of events is strongly time dependent, so the star formation history in a galaxy is another important parameter. Therefore, by calculating the evolution of events after a -function like star formation burst,   one gets a Green function for any arbitrary star formation history. ... The source evolution in a galaxy with given star formation rate is thus calculated as . ...

Next: Computation Up: userhtml Previous: Restoring an image . Because the basic interpolated calibrator gains do not determine the antenna gains perfectly at each time stamp, the quality of the resultant image suffers. Often the technique of self-calibration is used to make additional corrections to the antenna gains as a function of time. ... The main difference is than the model of the source is generally more complex than just assuming it's a point source at the phase centre. ...

PHYSICS Part IA Wednesday 19 January 2009 SELWYN COLLEGE REVISION TEST Attempt all three questions from section A and any two from section B. SECTION A ­ answer all questions. ... 5] A2 A3 SECTION B ­ answer two questions B4. ... 5] A uniform solid cylinder rolls from rest without slipping down a rough inclined plane, then along a horizontal section where the surface texture changes from rough to smooth, and finally up a second inclined plane with a perfectly-smooth surface. ...

In this section we present plots which may be used to rapidly estimate signal-to-noise ratio (SNR) for point sources with stellar spectra observed through popular WFPC2 filters. ... Dotted lines across the top of each plot indicate the onset of saturation. ... We look at Figure A2.10 and find this value on the horizontal axis. ... This exposure is well below the saturation lines in the plot, so saturation is not a concern. ... 0.45 Figure A2.1: Point Source SNR vs. V+AB for F160BW Filter. ...

... Problem 5. ... See figure 1 for the light curve of these narrow Nitrogen lines. ... Figure out the behaviour of each parcel of gas, and then add them all up to find the light curve. 5.4 (3pts) Using expression from problem 5.2, derive the expression for the time after SN explosion date, when the first light from the ionised ring reaches Earth. Using the expression from problem 5.2, derive the expression for the time after SN explosion date when the maximum brightness of the ring occurs. ...

Astronomy Discussion Forums . ... God and Science ћ SETI ћ Software ћ UFO ћ XEphem . ... SETI Assumes ET Doesnot Care About Can Being Detected What If . ... Post Message | ... My search on how to go undetected in space and SETI Search for Extraterrestrial Intelligence SETI. ... www.astronomy.net . About Astronomy Net | Advertise on Astronomy Net | ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... The degree of correlation between two parameters can visually be estimated by plotting them. Numerically this is expressed by the correlation coefficient : . ... When the correlation coefficient indicates a significant correlation, the functional relation is given by the regression line which is computed by least squares methods for normal distributions or maximum likelihood procedures (see Section ). ... Such transformation may also be used to make the variance of a variable homogenous. ...

Astro193 Homework 11 due on April 27, 2015 Periodogram exercise Generate 50 random data points Y(t) assuming a periodic model for the signal: Y (t|P ) = 42.0 + sin (2 t/P ) with a period P = 0.4 day and the time t nonevenly spaced over the total duration time T of: a/ T1= 5 days, b/ T2=10 days c/ T3=30 days. ... 2/ Calculate Nyquist frequency for each observation. 3/ Calculate a periodogram for these data using LombScargle algorithm (you can use the code available in R, IDL or Python SciPy). ...

... The current MOS procedure envisages a less complicated correction mechanism than for the PN. ... The CTI correction applies a scalar correction to the event list set, on an event by event basis, in order to correct for loss of charge which has occurred in reading out the CCD array. ... We expect to correct for a fixed amount of charge loss, and a fractional amount of charge loss, which depends on the number of row and column transfers completed. ... http://xmm.vilspa.esa.es/ xmmdoc/MOS/mos_cti.html ...

A problem, that can arise when moving from Fortran 77 to Fortran 90, is dependent on a usual deviation from the standard, and has to do especially with user programs. ... With many Fortran 77 implementations we wrote PROGRAM TEST REAL X WRITE(*,10) 10 FORMAT('Give X = ',$) READ(*,*) X WRITE(*,*) X END In Fortran 90 we use "non-advancing I/O" instead. ... In some old Fortran dialects the statement TYPE was used to write on a typewriter terminal and PRINT was used to write on the line printer. ...

... spectrum . ... SPECTRUM will compute synthetic spectra, line profiles equivalent widths, specific intensities, assuming LTE, from model atmospheres of early-type stars. ... sterne models . file containing model atmosphere in 2006 Sterne format . ... T=25000, log g=4.0, vt=0, 1400-1415A. a) NLTE model atmosphere, spectrum computed with SYNSPECv25 (black). b) LTE model atmosphere, same linelist in converted format, spectrum computed with SPECTRUM (red) using this input file and this linelist . ...

Next: Polarization efficiency: size/shape/orientation effects Up: Optical properties of cosmic Previous: The 2175? feature . To model the interstellar polarization one needs to calculate the forward-transmitted radiation for an ensemble of non-spherical aligned dust grains. ... Let non-polarized stellar radiation passes through a dusty cloud with a homogeneous magnetic field. ... The angle between the line of sight and the magnetic field is ( ). ... where the angle is connected with and ( ). ...

Astrophysics 405 Homework Assignment 4 Tully­Fisher Galaxies in the Expanding Universe Due 1999 April 15 This assignment is a ``dry lab'' simulation of a galaxy observation project. ... Images, spectra, and apparent magnitudes mB for a collection of nearby galaxies have been provided. ... For those galaxies you are unable to classify, assume type Sc. (g) Compute the T­F distance for each galaxy. ... 2 Galaxy Data Use the following data in your calculations. There are 32 galaxies in this sample. ...

By using the tools of sections (20) and (21), the mathematics of approximate solutions developed in (M-5), and assuming all orbits are circles, it is a relatively straightforward job to calculate the distance to the Lagrangian L1 point (or to L2). ... Let the gravitational constant be denoted by G , the mass of the Sun by M , that of Earth by m , the Earth's distance from the Sun by r and its velocity in its orbit by v . ... GMm / r 2 = mv 2 / r . and multiplying both sides by r / m . ...

... Yesterday, on October 16, 2015, the upper culmination of the Sun at the venue of the Olympiad was at 11:29:43 local time. ... According to an ancient legend of Middle Volga there was a constellation called W hite Leopard ( ­ Pardus Album) in the sky in the very past, in which the number of stars were exactly equal to the number of letters in the Greek alphabet, and the stars had magnitudes PaA ­ +0.10m, PaA ­ +0.20m, PaA ­ +0.30m, PaA ­ +0.40m, and so on with adding 0.10m till PaA. ... Spiral galaxy...

... By using the tools of sections (20) and (21), the mathematics of approximate solutions developed in (M-5), and assuming all orbits are circles, it is a relatively straightforward job to calculate the distance to the Lagrangian L1 point (or to L2). ... Let the gravitational constant be denoted by G , the mass of the Sun by M , that of Earth by m , the Earth's distance from the Sun by r and its velocity in its orbit by v . ... GMm / r 2 = mv 2 / r . and multiplying both sides by r / m . ...

... We present a computer program for modelling energy flux distribution and light curves of eclipsing binaries from far ultraviolet to infrared regions. The Roche model is assumed. Proximity effects of components (reflection of radiation and surface gravity darkening) are taken into account. ... Figure 1: The surface temperature distribution for Algol A-B system before (upper plot) and after (lower plot) correction for temperature due to the irradiation effect. ...

IBIS Data Analysis . ... IBIS . ... Flat Fielding - Introduction . The images obtained by IBIS will have intensity variations across the field of view that are not due to the solar image, but rather caused by instrumental effects that alter the observed intensity in each point of the field of view. ... IBIS Flat Fielding Techniques . ... Therefore, it is desirable to obtain the flat field measurements center on a point along the equator near the heliographic center of the solar disk. ...

... Searching for Far Out and Wandering Worlds . ... The Real Reality Show: Would aliens be anything like us? ... The SETI Institute is after alien signals. Assuming another world is beaming a 1-million-watt radio signal in our direction, how far away can that source be before the signal is lost in intergalactic noise? ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

The Chi-Square Goodness of Fit Statistic . This statistic enables us to test whether observed frequencies are close to . those we would expect. ... Expected frequencies . ... For example, if we . have an honest die we would expect 1/6 of all cases to show any of . ... So, for example, if we roll a die 60 times we would expect : . ... If we actually roll a die 60 times we wouldn't expect each of the faces . ... times each face actually comes up is the observed frequency for that face. ...