Wyniki wyszukiwania - BazTech

1

How Li and Paczyński Model of Kilonova Fits GW170817 Optical Counterpart

Kruszewski A.

Acta Astronomica

|

2018

|

Vol. 68, No. 3

205--211

EN

The original Li and Paczyński model of kilonova was compared with the observed bolometric optical light curve of the GW170817 electromagnetic counterpart. Perfect agreement is obtained for early observations up to 1.5 d since the time of merger.

2

On Estimating Non-Uniform Density Distributions Using N Nearest Neighbors

Woźniak P. R., Kruszewski A.

Acta Astronomica

|

2012

|

Vol. 62, No. 4

409--417

EN

We consider density estimators based on the nearest neighbors method applied to discrete point distributions in spaces of arbitrary dimensionality. If the density is constant, the volume of a hypersphere centered at a random location is proportional to the expected number of points falling within the hypersphere radius. The distance to the N-th nearest neighbor alone is then a sufficient statistic for the density. In the non-uniform case the proportionality is distorted. We model this distortion by normalizing hypersphere volumes to the largest one and expressing the resulting distribution in terms of the Legendre polynomials. Using Monte Carlo simulations we show that this approach can be used to effectively address the trade-off between smoothing bias and estimator variance for sparsely sampled distributions.

3

Modernizacja i intensyfikacja instalacji kwasu azotowego

Wilk M., Kruszewski A., Potempa M., Jancewicz R., Mendelewski J., Sławiński P., Inger M., Nieścioruk J.

Przemysł Chemiczny

|

2009

|

T. 88, nr 12

1315-1318

4

A Simple Method of Correcting Magnitudes for the Errors Introduced by Atmospheric Refraction

Kruszewski A., Semeniuk I.

Acta Astronomica

|

2003

|

Vol. 56, No. 3

241--248

EN

We show that the errors due to atmospheric refraction are present in the magnitudes determined with the Difference Images Analysis method. In case of single, unblended stars the size of the effect agrees with the theoretical prediction. But when the blending is strong, what is quite common in a dense field, then the effect of atmospheric refraction can be strongly amplified to the extent that some cases of apparently variable stars with largest amplitudes of variations are solely due to refraction. We present a simple method of correcting for this kind of errors.

5

Nearby Hipparcos Eclipsing Binaries for Color - Surface Brightness Calibration

Kruszewski A., Semeniuk I.

Acta Astronomica

|

1999

|

Vol. 49, No. 4

561--575

EN

This paper contains the list of Hipparcos eclipsing binaries that fulfill the following conditions: the star is classified in the Hipparcos Catalogue as EA-type eclipsing binary and its parallax is either larger than 5 mas or it is five times larger than its mean error. An eclipsing binary with known distance and with photometric and double-line spectroscopic orbits determined can be used in the process of calibrating the relation between the stellar surface brightness and the color that is crucial for the method of the distance determination by means of eclipsing binaries. This list is being published in order to draw attention of observers using small telescopes to these bright, potentially useful and in the most cases poorly observed objects. The advantages of the eclipsing binary method of the distance determination are discussed.

6

CCD Photometry of FO Aqr: The Intermediate Polar with Complex Spin Period Changes

Kruszewski A., Semeniuk I.

Acta Astronomica

|

1998

|

Vol. 48, No. 4

757--762

EN

CCD optical photometry of the intermediate polar FO Aqr is reported. We confirm that the spin period variability shows a complex behavior that cannot be represented well by means of a cubic fit. It seems that the rate of spin period changes has changed abruptly twice during 16 years since the object discovery.