## Multi-frequency synthesis technique based on maximum entropy method. On the importance of correction of the frequency-dependent VLBI core position shift

Transactions of IAA RAS, issue 24, 265–270 (2012)

**Keywords**:
radio source, radio brightness, multifrequency synthesis algorithm

### Abstract

We propose the multifrequency synthesis (MFS) algorithm with the spectral correction offrequency-dependent source brightness distribution based on the maximum entropy method. In order to take into account the spectral terms of nth order in the Taylor expansion for the frequency-dependent brightness distribution, we use a generalized form of the maximum entropy method. This is suitable for the reconstruction of not only positive-definite functions, but also sign-variable functions. With the proposed algorithm, we aim to produce both an improved total intensity image and a two-dimensional spectral index distribution over the source. We also consider the problem of the frequency-dependent variation of the radiocore positions of self-absorbed active galactic nuclei, which should be taken into account in a correct MFS.

### Citation

`A. T. Bajkova, A. B. Pushkarev . Multi-frequency synthesis technique based on maximum entropy method. On the importance of correction of the frequency-dependent VLBI core position shift // Transactions of IAA RAS. — 2012. — Issue 24. — P. 265–270.`

```
@article{bajkova2012,
abstract = {We propose the multifrequency synthesis (MFS) algorithm with the spectral correction offrequency-dependent source brightness distribution based on the maximum entropy method. In order to take into account the spectral terms of nth order in the Taylor expansion for the frequency-dependent brightness distribution, we use a generalized form of the maximum entropy method. This is suitable for the reconstruction of not only positive-definite functions, but also sign-variable functions. With the proposed algorithm, we aim to produce both an improved total intensity image and a two-dimensional spectral index distribution over the source. We also consider the problem of the frequency-dependent variation of the radiocore positions of self-absorbed active galactic nuclei, which should be taken into account in a correct MFS.},
author = {A.~T. Bajkova and A.~B. Pushkarev},
issue = {24},
journal = {Transactions of IAA RAS},
keyword = {radio source, radio brightness, multifrequency synthesis algorithm},
pages = {265--270},
title = {Multi-frequency synthesis technique based on maximum entropy method. On the importance of correction of the frequency-dependent VLBI core position shift},
url = {http://iaaras.ru/en/library/paper/863/},
year = {2012}
}
```

```
TY - JOUR
TI - Multi-frequency synthesis technique based on maximum entropy method. On the importance of correction of the frequency-dependent VLBI core position shift
AU - Bajkova, A. T.
AU - Pushkarev, A. B.
PY - 2012
T2 - Transactions of IAA RAS
IS - 24
SP - 265
AB - We propose the multifrequency synthesis (MFS) algorithm with the
spectral correction offrequency-dependent source brightness
distribution based on the maximum entropy method. In order to take
into account the spectral terms of nth order in the Taylor expansion
for the frequency-dependent brightness distribution, we use a
generalized form of the maximum entropy method. This is suitable for
the reconstruction of not only positive-definite functions, but also
sign-variable functions. With the proposed algorithm, we aim to
produce both an improved total intensity image and a two-dimensional
spectral index distribution over the source. We also consider the
problem of the frequency-dependent variation of the radiocore
positions of self-absorbed active galactic nuclei, which should be
taken into account in a correct MFS.
UR - http://iaaras.ru/en/library/paper/863/
ER -
```