MOJAVE ( Monitoring
Of Jets
in
Active galactic
nuclei with VLBA
Experiments) is a
long-term program to monitor radio brightness and
polarization variations in jets associated with active
galaxies visible in the northern sky. Approximately 1/3 of
these were observed from 1994-2002 as part of the VLBA 2
cm Survey. These jets are powered by the accretion of
material onto billion-solar-mass black holes located in
the nuclei of active galaxies. Their rapid brightness
variations and apparent
superluminal
motions indicate that they contain highly energetic
plasma moving nearly directly at us at speeds approaching
that of light. Our observations are made with the
world's highest resolution telescope: the Very
Long Baseline Array (VLBA) at wavelengths of 7 mm,
1.3 cm, and 2 cm, which enables us to make full
polarization images with an angular resolution better than
1 milliarcsecond (the apparent separation of your car's
headlights, as seen by an astronaut on the Moon). We are
using these data to better understand the complex
evolution and magnetic field structures of these jets on
light-year scales, close to where they originate in the
active nucleus, and how this activity is correlated with
gamma-ray emission detected by NASA's Fermi observatory.
For astronomers:
All calibrated (u,v) visibility and FITS data for the
MOJAVE and Boston U programs are available via html links
on the source
pages. If you are interested in Stokes Q,U,V (linear
and circular polarization) FITS images, please contact
us.
WHAT'S
NEW:
VLBA Flux Density Scaling Issue: The MOJAVE team, working with the OVRO 40m AGN monitoring group, has discovered a systematic error in the flux densities of all VLBA 15 GHz observations taking place sometime after early May 2019. All observations after that date have correlated flux densities that are between 10% and 20% too low. The MOJAVE team and NRAO are currently investigating the issue.
New Individual AGN Jet
Paper Published: The MOJAVE team has published a
detailed study of stationary features in the jet of BL Lac
( Arshakian
et al. 2020).
Press release:
https://mipt.ru/english/news/cosmic_quasars_embrace_1970s_fashion_trend
: Team member Yuri Y. Kovalev (Lebedev Physical
Institute, and Moscow Institute of Physics and Technology)
has led a study
using epoch-stacked image data from the MOJAVE survey
(available on the individual
AGN source pages). We have found that 10 AGN jets at
redshift < 0.07 show a transition from a parabolic to
conical shape. This suggests that this geometry transition
may be a common effect in AGN jets. The break is found to
occur at 10 ^5-10 ^6
gravitational radii from the active nucleus.
MOJAVE program approved until August 2021: We have
received priority 'A' status on the VLBA starting in Aug.
2019 to conduct monthly simultaneous 15+24+43 GHz
observations at 4 Gbps of 25
blazars, and regularly observe an additional
63 AGNs at 15 GHz (2 Gbps). This is the first large
scale high resolution multi-epoch study of Faraday
rotation measure and spectral gradients in AGN jets.
New Kinematics and Parent
Population Analysis Paper: We have analyzed the
pc-scale jet kinematics of 409 bright radio-loud AGNs
based on 15 GHz VLBA data obtained between 1994 August 31
and 2016 December 26. Our results combined with other
speeds from the literature indicate a strong correlation
between apparent jet speed and synchrotron peak frequency,
with the highest jet speeds being found only in low-peaked
AGNs. Using Monte Carlo simulations, we find best
fit parent population parameters for a complete sample of
174 quasars above 1.5 Jy at 15 GHz., and show that they
are consistent with powerful FR II class radio galaxies.
The manuscript was published
in ApJ in March 2019.
New MOJAVE Flux
Density-Limited Sample (1.5JyQC): Using data
from the VLBA, UMRAO, RATAN-600, and OVRO-40m telescopes,
we have constructed a new
complete '1.5 Jy Quarter Century' sample consisting
of all 232 non-lensed AGN north of declination -30 degrees
known to have exceeded 1.5 Jy in VLBA flux density at 15
GHz between 1994.0-2019.0.
VLBA
L Band Data: In 2010, D. Gabuzda and
collaborators at Univ. College Cork observed the original
MOJAVE AGN sample at 4 frequencies in L Band with the VLBA
to investigate jet polarization and Faraday rotation
properties. We have added the preliminary u,v visibility
data and images from this
program to the individual MOJAVE source pages in our
data
archive.
MOJAVE is a VLBA Key
Science Project:
The MOJAVE program has been designated a Key
Science
Project by NRAO, in recognition of its contributions
and impact on the astrophysics community.
Blazar Monitoring Program
List:
Most of the blazars in MOJAVE are monitored at other
wavelengths by a variety of instruments. This blazar
monitoring
list page contains a sortable table of all blazars
known to be monitored at optical wavelengths, as well as
known TeV-emitting AGNs and MOJAVE-monitored sources.
Superluminal Motion
Demonstration Applets and Lab Activities:
The MOJAVE collaboration has developed several software
applets that demonstrate the principle of apparent
superluminal motion. One is a Flash
software
applet developed by REU student Quinn Looker and
Prof. Matthew Lister of Purdue University, and the other
is
a 3-D Vpython-based simulation recently developed by Prof.
Dan Homan of Denison University. The Vpython
applet and an accompanying laboratory exercise for
an introductory astronomy level course can be accessed at
http://personal.denison.edu/~homand/superluminal/
Joint Fermi-MOJAVE
papers: We have found several strong
connections between the VLBA radio jet properties of
MOJAVE blazars and their Fermi-detected gamma-ray
emission. Details have been published in Lister
et al. 2011, in Pushkarev,
Kovalev,
&
Lister 2010, Savolainen
et
al. 2010, Pushkarev
et
al. 2009, Lister
et
al. 2009, and Kovalev
et
al. 2009. In addition, we continute to contribute to
multiwavelength studies of individual AGN, e.g. 3C390.3: Arshakian
et
al. 2010, 1510-089: Abdo
et
al. 2010, 3C 454.3: Vercellone
et
al. 2010, 1502+106: Abdo
et al. 2009, J0948+0022: Abdo
et al. 2009, and NGC 1275: Abdo
et al. 2009. For a full list please visit our publications
page.
The
MOJAVE
program
is supported under NASA-Fermi grants 80NSSC19K1579,
NNX15AU76G and NNX12A087G.
Any opinions, findings, and conclusions or
recommendations expressed on this website are those of
the authors and do not necessarily reflect the views of
NASA. The National Radio Astronomy Observatory is a
facility of the National Science Foundation operated
under cooperative agreement by Associated Universities,
Inc.
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