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RESEARCH FINDINGS FROM A.A. HAKOBYAN ET AL UPDATE UNDERSTANDING OF ASTROPHYSICS
Science Letter
May 19, 2009
"The determination of the supernova (SN) rate is based not only on
the number of detected events, but also on the properties of the
parent galaxy population. This is the first paper of a series aimed
at obtaining new, refined, SN rates from a set of five SN surveys,
by making use of a joint analysis of near-infrared (NIR) data,"
scientists in Armenia report (see also Astrophysics).
"We describe the properties of the 3838 galaxies that were monitored
for SNe events, including newly determined morphologies and their
DENIS, and POSS-II/UKST I, 2MASS and DENIS J and K-s and 2MASS
H magnitudes. We have compared 2MASS, DENIS and POSS-II/UKST IJK
magnitudes in order to find possible systematic photometric shifts
in the measurements. The DENIS and POSS-II/UKST I band magnitudes
show large discrepancies (mean absolute difference of 0.4 mag.),
mostly due to different spectral responses of the two instruments,
with an important contribution (0.33 mag rms) from the large
uncertainties in the photometric calibration of the POSS-II and UKST
photographic plates. In the other wavebands, the limiting near infrared
magnitude, morphology, and inclination of the galaxies are the most
influential factors which affect the determination of photometry of
the galaxies. Nevertheless, no significant systematic differences
have been found between any pair of NIR magnitude measurements,
except for a few percent of galaxies showing large discrepancies,"
wrote A.A. Hakobyan and colleagues.
The researchers concluded: "This allows us to combine DENIS and 2MASS
data for the J and K-s filters."
Hakobyan and colleagues published their study in Astrophysics (Five
supernova survey galaxies in the southern hemisphere. I. Optical and
near-infrared database. Astrophysics, 2009;52(1):40-53).
Science Letter
May 19, 2009
"The determination of the supernova (SN) rate is based not only on
the number of detected events, but also on the properties of the
parent galaxy population. This is the first paper of a series aimed
at obtaining new, refined, SN rates from a set of five SN surveys,
by making use of a joint analysis of near-infrared (NIR) data,"
scientists in Armenia report (see also Astrophysics).
"We describe the properties of the 3838 galaxies that were monitored
for SNe events, including newly determined morphologies and their
DENIS, and POSS-II/UKST I, 2MASS and DENIS J and K-s and 2MASS
H magnitudes. We have compared 2MASS, DENIS and POSS-II/UKST IJK
magnitudes in order to find possible systematic photometric shifts
in the measurements. The DENIS and POSS-II/UKST I band magnitudes
show large discrepancies (mean absolute difference of 0.4 mag.),
mostly due to different spectral responses of the two instruments,
with an important contribution (0.33 mag rms) from the large
uncertainties in the photometric calibration of the POSS-II and UKST
photographic plates. In the other wavebands, the limiting near infrared
magnitude, morphology, and inclination of the galaxies are the most
influential factors which affect the determination of photometry of
the galaxies. Nevertheless, no significant systematic differences
have been found between any pair of NIR magnitude measurements,
except for a few percent of galaxies showing large discrepancies,"
wrote A.A. Hakobyan and colleagues.
The researchers concluded: "This allows us to combine DENIS and 2MASS
data for the J and K-s filters."
Hakobyan and colleagues published their study in Astrophysics (Five
supernova survey galaxies in the southern hemisphere. I. Optical and
near-infrared database. Astrophysics, 2009;52(1):40-53).