Welcome!
Welcome to the issue 8 of the e-
MERLIN newsletter. Happy New
Year! We will be publishing e-
MERLIN-related news and
science highlights, including calls
for proposals, adverts for summer
schools and links to e-MERLIN
partners, including the recently
commenced ACME project. If you
would like to contribute to the e-
MERLIN newsletter, please get in
touch at:
emerlin.support@jb.man.ac.uk !
Zooming into the quasar Feedback
with e-MERLIN
Galaxy evolution models and simulations require a
process called ‘feedback’ to regulate galaxy growth.
However, there is ongoing debate around the dominant
energy injection mechanism (i.e., jets, accretion-disk
winds or direct radiation pressure on the host galaxy
gas) and to what level they can have an appreciable
impact on galaxy evolution. Multi-resolution radio
observations can be used to help solve this key piece of
the AGN feedback puzzle.!
The Quasar Feedback Survey includes 42 low redshift (𝑧
< 0.2) quasars selected from a parent sample of
spectroscopically identified AGN in the SDSS. These
targets are predominantly ‘radio quiet’ quasars. The e-
MERLIN data enabled measurements of radio structures
on ∼ 10s-100s pc scales, which is an order of
magnitude smaller than the structures measured in the
existing VLA images of the same targets.!
The targets showed a wide range of morphology on
sub-kiloparsec scales, with compact cores, knots,
extended collimated structures and more diffuse
structures. Half of the sources were identified as jet-like
from their radio morphology, but a significant fraction of
the total radio luminosity in this sample was typically not
located in the compact, sub-kiloparsec structures
traced by e-MERLIN. Instead, previous VLA maps have
showed diffuse emission likely associated with jets or
lobes. By using various diagnostics, it was shown that
more than three quarters of the sample could be
identified as having radio AGN activity, an increase on
the 57% if the VLA maps were taken in isolation, thanks
to the increased constraints on morphology and
brightness temperatures at the higher resolution of e-
MERLIN. This work highlights the importance of using a
wide range of radio images, tracing sub-kiloparsec
scales through to 10s of kiloparsec scales.!
Read the full paper here (Njeri et al. 2025, MNRAS,
Volume 527, Issue 1, p 942)!
User Newsletter
Issue 8 4 February 2025!
2 of the 4 targets with clearly defined
jetted structures
Announcements
Effelsberg Call for Proposals.
Deadline 4 February 2025.
Click here for further information!
INAF Call for Proposals
Deadline expected in March
2025. Click here for further
information!
EVN Call for Proposals.
Deadline 1 June 2025. Click
here for further information!
Meetings/Workshops!
AstroORDAS Meeting
Lausanne + hybrid, Switzerland,
5-6 February 2025, Click here
for more details!
SKA Science Meeting Gurlitz,
Germany, 16-20 June 2025,
Click here for more details!
RAS National Astronomy
Meeting Durham, UK, 7-11 July
2025, Click here for more details!
The Dynamic Radio Sky
Sydney, Australia, 28 July 1
August 2025. Click here for
more details!
Extragalactic jets at all scales
Crete, Greece, 25-29 August
2025. Click here for more details!
Cold Gas outflows from a new-born
radio jet
The young (<5000 years old) radio galaxy 4C 31.04 is
an excellent object to study how young radio jets
emitted from central super-massive black holes
(SMBHs) interact with their environments, leading to
feedback into the interstellar medium. !
By using global VLBI, including e-MERLIN, it is
possible to map the distribution and kinematics of
cold gas at a spatial resolution of 2 pc in 4C 31.04. In
addition, the southern radio jet is driving an outflow
only 35 pc in projection from the SMBH. The e-
MERLIN baselines helped to eliminate the possibility
that the outflowing gas was at a much larger distance
from the centre of the galaxy.#!
Read the full paper here (Murthy et al. 2024, A&A,
Volume 688, id. A84)!
e-MERLIN Cycle 19 results
announcement
The results for cycle 19 of the e-MERLIN call for
proposals have now been released to PIs. The
successful programmes are listed here.
The young radio jets in 4C 31.04
Searching for winds in radio-quiet
AGN
Active Galactic Nuclei (AGN) can show evidence of
radio jets, winds, an accretion disc corona or star
formation, depending on their radio power.
Disentangling these different processes can be tricky
without multi-frequency sensitivity high-resolution
radio observations. In a new study including EVN+e-
MERLIN data, the radio emission of 19 Palomar-Green
radio-quiet quasars is investigated and compared to
the C IV emission line blue excess to find objects with
winds from the broad line region around the AGN. !
In the overall sample of 19 sources, nearly three
quarters show signs of a either both radio and BLR
winds or neither. Most of these wind sources are
consistent with high Eddington ratios, while nearly all
the non-wind sources have low Eddington ratios,
indicating that the AGN winds are likely driven by
radiation pressure.!
Read the full paper here (Chen et al. 2024, ApJ,
Volume 975, Issue 1, id 35, pp 18)!
Eddington radio as a function of radio
spectrum
Eagerly awaiting the
upcoming outburst of
T Cor Bor!
The recurrent nova T Corona
Borealis (T Cor Bor) is overdue
an outburst after its large one 80
years ago. At e-MERLIN, we’re
eagerly awaiting the upcoming
outburst and were contacted by
the British Broadcasting
Company (BBC) to discuss it.
When T Cor Bor goes into
outburst it will be possible to see
with the naked eye from all of
the northern hemisphere.
Our e-MERLIN Support
Scientist, David Williams-
Baldwin joined the BBC
Breakfast team as part of a
special report, which can be
found here.
David on the BBC Breakfast Sofa
(photo credit: Tracey from the
BBC)