| dc.contributor | ALBERTO CARRAMIÑANA ALONSO | |
| dc.contributor | VAHRAM CHAVUSHYAN | |
| dc.contributor | LUIS CARRASCO BAZUA | |
| dc.creator | VICTOR MANUEL PATIÑO ALVAREZ | |
| dc.date | 2012-02 | |
| dc.date.accessioned | 2023-07-25T16:21:19Z | |
| dc.date.available | 2023-07-25T16:21:19Z | |
| dc.identifier | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/310 | |
| dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/7805530 | |
| dc.description | In this work it was determined if there exist delays between the emissions in different
bands in 16 Fermi/LAT detected blazars, via the cross-correlation function (CCF).
The bands we are working with are: gamma-rays (0.1-300 GeV), optical V band,
near-infrared J, H and Ks bands (observation frame) and emission lines (object rest
frame). We also want to investigate the performance of distinct methods used to
obtain the cross-correlation function under different conditions, and we pretend to
point out their flaws and strengths, so that in the future we can make the correct
decision about what method to use, depending on the specific characteristics of the
data available.
The cross-correlation analysis was carried out by three different methods discussed
previously in the literature, the interpolation method (Gaskell & Sparke, 1986), the
discrete cross-correlation function (Edelson & Krolik, 1988) and the Z-transformed
discrete correlation function (Alexander, 1997). The idea behind using more than
one method is to increase the sturdiness of the results obtained. Nonetheless, some
modifications were made with respect to the original methods due to some problems
present in these, mainly to correct for the nonlinearity of the AGN light curves.
Our results show that for all objects, the three NIR bands vary simultaneously. For
four objects of our sample (3C 273, Mrk 501, PKS 2155-304, and PMN J0808-0751),
no correlation is found between any of the bands available in this study. For the
remaining twelve, a correlation was found between the V band and the NIR bands;
in most of them indicating that the V band and the NIR bands vary simultaneously
or with small delay. For just 3 objects (3C 454.3, PKS 0235+164, and PKS 1510-089)
was found a correlation between the gamma-ray emission and the V band; for the
same three objects is found a correlation between gamma-ray emission and the NIR
bands.
In this work, we arrived to the conclusion that due to the different flaws existent in
the three methods to compute the CCF, there is not a single method better than the
others; and if we want better robustness in the results it is necessary to use more
than one method. | |
| dc.format | application/pdf | |
| dc.language | eng | |
| dc.publisher | Instituto Nacional de Astrofísica, Óptica y Electrónica | |
| dc.relation | citation:Patiño-Alvarez V.M. | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.rights | http://creativecommons.org/licenses/by-nc-nd/4.0 | |
| dc.subject | info:eu-repo/classification/Métodos de correlación/Correlation methods | |
| dc.subject | info:eu-repo/classification/Blazars/Blazars | |
| dc.subject | info:eu-repo/classification/Núcleos galaticos activos/Active galatic nuclei | |
| dc.subject | info:eu-repo/classification/cti/1 | |
| dc.subject | info:eu-repo/classification/cti/21 | |
| dc.subject | info:eu-repo/classification/cti/21 | |
| dc.title | Multifrequency study of variability of Fermi/LAT Blazars | |
| dc.type | info:eu-repo/semantics/masterThesis | |
| dc.type | info:eu-repo/semantics/acceptedVersion | |
| dc.audience | students | |
| dc.audience | researchers | |
| dc.audience | generalPublic | |
