Submit an abstract for the SKA Pathfinders session at NAM!

May 2024

Join a plethora of other SKA Pathfinder scientists including e-MERLIN at NAM 2024 in Hull.

We are happy to announce a parallel session entitled “Era of SKAO Pathfinders – Pushing the Boundaries of the Radio Sky” will be held at NAM 2024 hosted in Hull. The session has 2, 2-hour slots on the Monday of the conference (15th July) and we are accepting abstracts with the deadline of 3rd June.

The Square Kilometre Array Observatory (SKAO) will revolutionise our understanding of the radio sky and with the SKAO-Mid prototype dish having achieved first light, the future of radio astronomy is in sight. To prepare for such an impressive instrument, SKAO pathfinders (such as, LOFAR, e-MERLIN, MeerKAT) have already pushed, and are continuing to push, the boundaries of what is possible. It is important to show the wider astronomical community the vast science that has been conducted at low to mid radio frequencies and what has already been done to prepare for the transformative results the SKAO will bring.

This session will enable the UK astronomy community, particularly early-career researchers (ECRs), to present their cutting-edge research conducted using SKAO precursors. We will welcome a wide scope of science to this session to emphasize the widespread impact that current radio facilities are having on science topics such as galaxy evolution, AGN, transients, pulsars and cosmic magnetism as well as technical challenges such as the confrontation of large data sets in radio imaging. Discussion of how such research prepared us for the SKAO will help us understand the path toward its survey operations.

Find out more about the NAM here.

The paradigm of U/LIRGs with e-MERLIN and VLA

April 2024

Using a novel method to decompose AGN activity from star formation, the star formation rate is found to be higher than previous studies in four Ultra-Luminous Infrared Galaxies.

The class of objects called Ultra-Luminous and Luminous Infrared Galaxies (U/LIRGs) are bright infrared emitters. They are characteristic of massive merger interactions and high rates of star formation, at different spatial scales, both in nuclear regions (<0.2-1 kpc) and on large-scale structures. Understanding how star formation takes place in these systems plays a pivotal role in studying their dynamics and evolution. Alongside this, characterising local U/LIRGs with high-angular resolution helps us to understand the star-formation and mass assembly of the Universe at higher red-shifts.

The radio emission in the nuclear regions of these systems is a mixture of AGN activity, starburst, jets and star formation. Decoupling these individual processes to study them separately has proven difficult and led to inaccurate measurements of star formation rates or AGN power. The PARADIGM project, alongside with the e-MERLIN Legacy Project LIRGI, aims to measure the radio emission on 10s pc-scales, thus disentangling the emission mechanisms.

In this recent work, Geferson Lucatelli and collaborators investigated an alternative approach that uses combined interferometric arrays (e-MERLIN + VLA) at 6 GHz to obtain a multi-scale tracer for star-formation. Using e-MERLIN, the compact AGN emission is disentangled from the nuclear extended radio emission, and was thus used to quantify the nuclear star-formation. The VLA data helped to probe the larger-scale emission, translating it to star formation without the contamination from possible AGN emission, which was removed with the e-MERLIN data.

The main result of the pilot study showed that the total star formation rate (SFR) of these sources can be significantly higher when using a multi-scale metric, since it takes into account the nuclear star formation. This effect provides a boost to the total SFR output, and in some occasions, dominates the large-scale SFR.

The next phase of this work, is to expand the same concepts for the full LIRGI sample (42 U/LIRGs), and using multi-wavelength observations, separate different emission mechanisms (thermal and non-thermal) across various frequency and spatial scales, on a component-by-component basis.

Read the full article here (Lucatelli et al. 2024). The source code can be found at Github

Milliarcsecond Localisation of the Hyperactive Repeating FRB 20220912A

March 2024

An astonishingly active repeating fast radio burst source has been pinpointed to milliarcsecond precision, thanks to an ad hoc array of European VLBI Network and e-MERLIN dishes.

The majority of fast radio bursts (FRBs) are observed as single, millisecond-duration radio pulses originating from extragalactic distances. While a small fraction (~3%) of these sources repeat sporadically and infrequently, FRB 20220912A stands out as one of the most active FRB sources known to date. Discovered by the Canadian Hydrogen Intensity Mapping Experiment FRB project (CHIME/FRB), this single source contributed a few percent of the entire all-sky rate of FRBs above a fluence threshold of 100 Jy ms during its peak activity! Consequently, it has become the focus of numerous follow-up campaigns, including localization efforts involving e-MERLIN.

In a recent paper, Danté Hewitt and colleagues from the PRECISE FRB-localisation programme, detected 150 bursts from the hyperactive repeater FRB 20220912A, allowing it to be pinpointed to a precision of a few milliarcseconds - hundreds of times more precise than previous localisations. This revealed that FRB 20220912A resides closer to (albeit still offset from) the center of its host galaxy, which was earlier identified using a localisation from the Deep Synoptic Array 110 (DSA-110). The observations also ruled out the presence of a compact persistent radio source at the FRB location, a phenomenon observed in some other active repeaters, and theorised to be hypernebulae powered by neutron stars. Instead, the persistent radio emission on larger angular scales is most likely due to star formation in the host galaxy.

PRECISE (Pinpointing REpeating ChIme/frb Sources with EVN dishes) is a project to localise repeating FRBs to the best-possible precision by making use of ad-hoc arrays of radio telescopes. Approximately half of these dishes also form part of e-MERLIN. Typically, angular resolution on the order of milliarcseconds is achieved in PRECISE FRB localisations. In the past this has facilitated not only the identification of host galaxies of FRB sources, but also enabled detailed studies of their local environments using, e.g., the Hubble Space Telescope. Such milliarcsecond localizations will prove particularly valuable in the coming era, where optical telescopes like the Extremely Large Telescope will match the milliarcsecond resolution of VLBI, allowing us to zoom-in on the local environments of FRB sources at the (sub-)parsec level in their host galaxy; perhaps even leading to the discovery of extragalactic stellar counterparts to FRB sources.

Read the full article here (Hewitt et al. 2024).

Searching for high-brightness temperature AGN cores in surveys using high-resolution radio data

March 2024

Extragalactic Survey fields provide a rich hunting ground for Active nuclei, but multiple resolution interferometers are needed to tell them apart from star formation.

Deep radio surveys of extragalactic legacy fields trace a large range of spatial and brightness temperature sensitivity scales, and therefore have differing biases to radio-emitting physical components within galaxies. This is particularly true of radio surveys performed at ≲1 arcsec angular resolutions, and so robust comparisons are necessary to better understand the biases present in each survey.

Ann Njeri and her team performed a multi-resolution analysis of 24 sources detected in a new Very Long Baseline Array (VLBA) survey of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey Great Observatories Origins Deep Survey-North field. This VLBA data were augmented by ~0.1-1 arcsec angular resolution data provided by the European VLBI Network, the Very Large Array (VLA) and the enhanced-Multi Element Remotely Linked Interferometry Network (e-MERLIN).

The high brightness temperatures of these sources (> 1 million Kelvin) confirm AGN cores as measured by VLBI. These sources would often be missed or ambiguous in lower-resolution radio data of the same sources. By combining VLA and VLBI measurements, they find evidence that most of the extended radio emission is also AGN dominated, with only ~13% of the sources showing a likelihood of being star formation-dominated. Combining e-MERLIN and VLBI reveals potentially hybrid systems that are missed in either individual surveys. This survey demonstrates the importance of wide-field multi-resolution (arcsecond-to-milliarcsecond) coverage of the faint radio source population, for a complete picture of the multiscale processes within these galaxies.

Read the full article here (Njeri et al. 2024).

ORP Multi-facility call announced

March 2024

An opportunity to propose for 18 facilities simultaneously in the radio and optical has been announced through the Opticon RadioNet Pilot programme.

The Opticon RadioNet Pilot (ORP) has launched as new Multi-Facility Call for Proposals to use multiple observatories for the same scientific project. 18 radio and optical facilities are available and proposers are asked to submit for time on more than one facility as part of this call. The deadline is the 9th April 2024 at 1400UTC.

Find out more about the multi-facility call here.

e-MERLIN Data School announcement

March 2024

The 2nd e-MERLIN data school has been announced, taking place in Manchester from 13-15 May 2024

e-MERLIN support staff, with funding support from the Opticon RadioNet Pilot, will be running a data school at the University of Manchester from 13-15 May 2024. The purpose of this school is to show participants how to reduce e-MERLIN data using the e-MERLIN CASA Pipeline. The school is designed for those with some radio astronomy knowledge. Priority will be given to PhD students and early career researchers. The three-day school will include calibration, imaging and self-calibration tutorials, with an opportunity to bring your own data (BYOD) to get expert help with your own e-MERLIN projects. We expect to be able to have space for up to 10 participants.

Find out more about the 2nd e-MERLIN data school here.

OH MegaMasers in Arp 220 at intermediate resolution, using MERLIN + EVN

February 2024

The complex OH line activity in Arp 220 has been detected by combining MERLIN and EVN data.

Arp 220 is a nearby system comprised of two merging galaxies triggering significant star formation in the merger. It was the first system to be detected with hydroxyl (OH) MegaMaser emission, afterwards identified as an archetypal Ultra-Luminous infrared Galaxy (ULIRG). Since that first discovery many more ULIRGs have been discovered with OH MegaMaser emission. ULIRGs tend to be found at higher redshift, making Arp 220 a useful nearby laboratory for the ULIRG population.

In this work by Willem Baan and colleagues, observations obtained in 2003 using MERLIN and EVN have been analysed and combined to study the multiple masering components in Arp 220. The data combination was performed in order to make an intermediate resolution dataset to provide a clearer view of the source. MERLIN on its own does not provide the requisite resolution but detects the larger scale regions; EVN resolves those extended emission regions and only detects higher brightness temperature components.

At intermediate resolution with MERLIN and EVN, the spectral line emission in Arp 220 separates into compact and extended regions distributed across the two nuclei. The strong compact components represent star-formation-related maser sources and provide the first accurate estimate of the systemic velocities of these two very obscured nuclei. On the other hand, the more dominant extended emission regions belong to foreground material at a much lower velocity that is part of the surrounding debris structures, generated by the galactic merger. The far-infrared radiation field from the ongoing star-formation in the nuclear regions serves to excite the OH molecules in those foreground regions. In turn, this results in maser amplification of the radio background as well as re-amplification of the compact components in the nuclear regions.

The results of the MERLIN/EVN synthesis have provided a detailed look at the masering process in Arp 220 showing that indeed excited foreground material can result in amplification of the radio background in the galaxy. This can generate the observed powerful MegaMaser emissions not only of OH, but also those of other masering molecular species. Such a scenario has been proposed along with the first discovery of the OHMM emission in Arp 220, but it had not been verified in detail.

Read the full article here (Baan et al. 2023).

UK SKA regional centre webinar series commences

February 2024

Join the UK SKA regional centre for their first webinar on 7th March 2024!

The UK's SKA regional centre (UKSRC) are starting a monthly webinar series focussing on topics related to the UKSRC and SKAO, including (but not limited to) demonstrator cases; SKA science topics; career pathways; relevant software; tools and data; SKAO Science Data Challenges and project updates. The inaugural webinar is on March 7th 2024 at 12:00 (GMT), with the title "Introducing UKSRC" and led by co-directors Louise Chisholm and Rob Beswick.

For more information about the upcoming webinars and stay up to date, please visit the UKSRC webpage. Also follow the UKS on Twitter & LinkedIn

Re-visiting NGC 1068 with the upgraded e-MERLIN and VLA telescopes

January 2024

By combining new datasets with the upgraded VLA and e-MERLIN telescopes, new images of NGC 1068 show the full jet structure for the first time.

NGC1068 is an archetypal Seyfert galaxy with an active nucleus producing large-scale jet structures. These structures, first observed in the 1980s and 1990s with MERLIN and the old VLA, have compact components and larger diffuse lobes north and south of the core region which interact with the gas and dust in the galaxy. As NGC1068 is a nearby galaxy, the study of it's radio jets is important for understanding how galaxies and active black holes co-evolve. Multiple studies with ALMA show molecular clouds that are shaped and plausibly powered by the radio jet structures. More recently, neutrino emission has been found to be co-incident with NGC1068, suggesting that either the active black hole or the jet is responsible for neutrino emission. New data obtained over the last ten years with the upgraded VLA and e-MERLIN interferometers now enable new studies to find the origin of this emission and study in-depth the affect the radio jet has on the molecular gas.

By combining the VLA and e-MERLIN high sensitivity data, Isaac Mutie, a PhD student at Technical University Kenya has created new images which show the full jet structure at multiple spatial resolutions simultaneously for the first time (see figure above). The new images are more sensitive than the previous observations and reveal a new component, S2a, south of the nucleus. In addition, component C was shown to be variable over the observing timeline between previous studies in the 1990s and the new data from the last ten years. It is still unclear what is causing this variability. Finally, it was shown that the NE jet lobe is powerful enough to drive the molecular outflows observed in ALMA data, showing further the need for multi-wavelength observations of this important source.

Read the full article here (Mutie et al. 2024).

Dealing with irregular PSFs in radio images using e-MERLIN and VLA

January 2024

Simulations of e-MERLIN and the VLA examine a systematic error present in all radio interferometric images employing CLEAN-based deconvolution methods.

An interferometer acts like the lens in an optical telescope, focusing the incoming radio waves. However, it differs in that one can conceptualize it as a telescope with perforations in the lens, preventing the generation of a clear image of the sky. Often this distortion is due to the point-spread function, which distorts the light across the image. The PSF is present in every single observation. The effect of the PSF is removed through a process called deconvolution which typically employs the CLEAN group of algorithms (see below). In these algorithms, the PSF is removed from the flux of the source and an estimate of the instrumental response (known as restoration) with a filled aperture (a lens without the holes) is used to produce the image.

Nevertheless, the restoration step introduces a systematic error in measured flux densities, particularly when dealing with a highly irregular PSF. This occurs when the estimate of the filled aperture response is inaccurate, as highlighted by Jörsäter and van Moorsel (1995). Historically, this effect has been overlooked, thanks to the excellent imaging performance and well-behaved PSFs of many contemporary interferometers. However, the forthcoming generation of instruments may face challenges in this regard. Radcliffe et al. addressed this issue by quantifying the impact of an irregular or poorly behaved PSF and the subsequent deconvolution process on the measured flux densities of astronomical objects. Their findings revealed potential errors that can range from a few per cent to over 250 per cent, a substantial discrepancy that demands consideration (see the figure below).

This paper underscores the critical importance of correcting for this effect. The authors present various solutions, enabling astronomers to accurately measure the brightness of their favourite astronomical objects despite the challenges posed by irregular PSFs and the deconvolution process.

Read the full article here (Radcliffe et al. 2024).

e-MERLIN Cycle 17 results announcement

December 2023

The e-MERLIN Time Allocation Group met on 11th December 2023 to consider proposals for Cycle-17. Proposals were received for L-Band (1.3-1.7 GHz), C-Band (4.5-7.5GHz), and K-Band (19-25 GHz). The amount of time approved is set by existing programme observation requirements, scheduling and engineering constraints, and by EVN commitments within the Cycle-17 period.

The e-MERLIN Cycle 17 call for proposals list of accepted proposals is below (in no particular order). The next call for proposals is anticipated in Spring 2024.

  • Accretion in Bipolar PN Hb12
  • Imaging the Central Engine of AGN powered Outflows
  • Finding the "Missing Flux" in PG 1149-110
  • The e-MERLIN view of the radio counterpart of GW events during O4
  • Comprehensive Study of a Dual AGN System J104454+354055 with e-MERLIN and LOFAR-VLBI: Probing AGN Jets, Lobe Emission, and Dynamics
  • High-resolution view on a kilo-parsec scale radio jet at z=6.1
  • The lensed radio-quiet quasar WISE2329-1258
  • Localising repeating FRBs with VLBI -- the need for eMERLIN
  • A radio view of the first changing multiplicity lensed quasar
  • Revealing dense circumnuclear regions with observations of an extreme coronal line emitting TDE
  • e-MERLIN monitoring of newly discovered slow jets from GRS 1915+105
  • Searching for the radio emission from the nucleus of M31 with e-MERLIN
  • Continued eMERLIN monitoring of ZTF22aaajecp/AT2022cmc: the first jetted tidal disruption event in a decade
  • Spectral evolution properties of a nuclear radio outburst from a massive quiescent galaxy
  • e-MERLIN observations of radio-quiet quasars for revealing the multi-scale radio emission structure
  • E-MERLIN Observations for Super-Eddington Accreting Quasar
  • The jewel in the crown, T Corona Borealis: the nearest recurrent nova poised to go into outburst
  • Mini-AGN NGC 4395: a pc-scale thermal outflow with a termination shock?

e-MERLIN detects the anticipated radio-optical offsets in high redshift candidates of sub-kpc dual SMBHs

November 2023

Gaia astrometric jitter was used to select dual SMBH candidates and the method shows promise with e-MERLIN follow up observations

Dual super massive black holes (SMBH) may appear in the post-merger stage of galaxies, which could play a key role in galaxy formation and evolution. As time goes by, dual SMBHs would get closer to each other due to dynamical friction, form binary SMBHs with a compact orbit and finally coalesce. Searching for close (∼kpc or sub-kpc) dual SMBHs, the progenitors of coalescing SMBHs, thus are essential to probe their dynamical evolution as well as the process of galaxy merging, especially at high redshifts when galaxy mergers occur much more frequently. Such dual SMBHs may appear as a dual AGN (active galactic nuclei) if both SMBHs are accreting, or an off-nucleus AGN, if only one SMBH is active. However dual and off-nucleus AGN were previously found mostly at low redshifts or large separations (> 10 kpc).

In a recent work, Haochen Wang and his team obtained high resolution e-MERLIN images of 5 candidates of high redshift dual SMBHs. These candidate quasars (luminous AGN) were pre-selected with clear astrometric jitters in Gaia EDR3, as the stochastic flux variabilities of the dual or off-nucleus quasar could yield astrometric variation of the photocenter of the dual-SMBH system. e-MERLIN observations revealed a single compact radio source for each candidate. Remarkably, four of them exhibit significant radio-optical offsets, which represent for the anticipated separations between one radio loud nucleus and the optical photocenter of a dual-SMBH system. Such radio-optical offsets are hardly seen in normal quasars, thus strongly favor the scenario of dual or off-nucleus quasars. The team confirms the projected separations of the candidate dual SMBHs could be as small as sub-kpc, and highlights the unique capability of high-resolution radio images to investigate close dual SMBHs.

Read the full article here (Wang et al. 2023).

VLBI Observations of a sample of Palomar-Green quasars

October 2023

Combining e-MERLIN with other VLBI arrays provides insight into radio-quiet quasars radio emission mechanisms

Very long baseline interferometry can be a powerful tool for providing insights into the origins of the nuclear radio emission in quasars. In radio-quiet quasars (RQQs), it is especially important as the radio emission can be due to the presence of a radio jets from an accreting AGN, winds, star formation, coronae, or a combination of the above. In lower-resolution studies, it is hard to disentangle these processes, but at sub-arcsecond resolution, a high-brightness temperature core can be attributed to the presence of jets or coronae from an accreting AGN, rather than star formation or winds. The spectral index, morphology and flux densities of the source also give clues to the source of the emission too. By combining the information from multiple arrays, it is possible to get a statistical understanding of the contribution of these different processes to the observed radio emission.

In these works, published by Monthly Notices of the Royal Astronomical Society, Ailing Wang and her team observed 20 quasars, comprising 4 radio loud (RLQs) and 16 RQQs, from the Palomar Green sample, using the VLA, VLBA, and EVN+e-MERLIN measurements at different resolution scales. In 10/16 RQQ cases, radio emission was unequivocally detected in the VLBA data, with 8 of those exhibiting a compact core. They noticed a division in the RLQs and the RQQs at ~30mJy, with RQQs likely due a combination of star formation and AGN activity. Moreover, the RQQs in their study proved to be highly resolved, due to extended jets or relic emission. One source, PG 0050+124, which was observed with EVN+e-MERLIN demonstrates this well. The combination of longer exposure time, and use of intermediate and long baselines from the e-MERLIN/EVN antennas enabled a noise level of 9µJy/beam, about 2.5 times lower than the noise in the VLBA image at a comparable frequency. Thanks to its impressive sensitivity, the EVN+eMERLIN image of PG 0050+124 unveils a more intricate jet structure.

Read the first article here (Wang et al. 2023a).

Read the second article here (Wang et al. 2023b).

LeMMINGs VI: Investigating the influence of the bulge on AGN activity and host galaxy evolution with Hubble and e-MERLIN

September 2023

Hubble and e-MERLIN observations link AGN and bulge properties in the LeMMINGs survey

The active galactic nucleus (AGN) at the galaxy centre and star formation in the bulge play a crucial role in moderating the growth and evolution of galaxies. The relationship between the mass of the bulge and the mass of the central accreting supermassive black hole powering the AGN is firmly established, with the two growing together. For nearby galaxies, distinguishing between the AGN and the bulge is possible due to the AGN's much higher central surface brightness in the optical, but this is not true for low-luminosity AGN. Furthermore, other nuclear features, e.g., rings and bars can complicate matters, but using high resolution e-MERLIN radio data and Hubble optical data, it is possible to discriminate the AGN from other sources of emission. The resolution of Hubble is comparable to that of e-MERLIN at 1.5 GHz, making the two a perfect synergetic pair for exploring the effect that bulge properties have on AGN, which is one of the goals of the LeMMINGs survey.

The e-MERLIN legacy project (LeMMINGs) provides high sensitivity radio observations of 280 nearby galaxies at 1.5 and 5 GHz, with a milli-arcsecond resolution to detect nuclear radio emission, identifying low-luminosity AGN and supernova remnant shells which can trace star formation. As part of this project, the LeMMINGs team has recently published 1.5 GHz e-MERLIN radio data for the full sample of 280 nearby galaxies. In a subsequent study, the team used data from the Hubble Science Archive and performed multi-component decompositions of optical images for 173 out of 280 galaxies and quantify the impact of various galaxy components (bulge, disc, AGN, bar, ring, spiral arms, and star clusters) on the optical galaxy profile. This allowed them to accurately measure optical bulge properties. In this work, Bil Dullo and the LeMMINGs team investigated the link between the radio core luminosity and the properties of the host bulge as well as its surrounding environment. When compared to the radio data, bulge dominance is linked to brighter radio core luminosities, with the both AGN and radio detection fractions increasing with the bulge mass. Furthermore, the analysis reveals a transition from AGN-dominated radio emission in massive bulges to stellar-driven processes in low-mass bulges. Radio-loud hosts preferred early-type morphology, but no obvious dependence on environment was found for radio loudness, nuclear radio activity, and the AGN fraction at a fixed bulge mass. Radio-loud and radio-quiet hosts are indistinguishable in terms of the Sersic index and ellipticity of the bulge.

Read the full article here.

Read more LeMMINGs articles here.

e-MERLIN Data School announcement

September 2023

The 1st e-MERLIN data school has been announced, taking place in Manchester from 23-25 October 2023

e-MERLIN support staff, with funding support from the Opticon RadioNet Pilot, will be running a data school at the University of Manchester from 23-25 October 2023. The purpose of this school is to show participants how to reduce e-MERLIN data using the e-MERLIN CASA Pipeline. The school is designed for those with some radio astronomy knowledge. Priority will be given to PhD students and early career researchers. The three-day school will include calibration, imaging and self-calibration tutorials, with an opportunity to bring your own data (BYOD) to get expert help with your own e-MERLIN projects. We expect to be able to have space for up to 10 participants.

Find out more about the 1st e-MERLIN data school here.

e-MERLIN Cycle 16 results announcement

July 2023

The e-MERLIN Time Allocation Group met on 13th July 2023 to consider proposals for Cycle-16. Proposals were received for L-Band (1.3-1.7 GHz), C-Band (4.5-7.5GHz), and K-Band (19-25 GHz). The amount of time approved is set by existing Legacy programme observation requirements, scheduling and engineering constraints, and by EVN commitments within the Cycle-16 period.

The e-MERLIN Cycle 16 call for proposals list of accepted proposals is below (in no particular order). The next call for proposals is anticipated in Autumn 2023.

  • Precise calorimetry of large-scale jets from black hole X-ray binaries
  • The origin of the compact 50 mas emission in Radio Quiet Quasars
  • High fidelity mapping of the OH maser shell of OH55.0+0.7
  • The e-MERLIN view of the radio counterpart of GW events during O4
  • Cosmic telescopes: peering through dark matter to understand RQQ radio emission
  • Cosmic telescopes: witnessing the emission mechanism of radio quiet quasars
  • Using variability to deconstruct accretion in jet systems around forming massive stars
  • Spectral structure of the radio galaxy 3C 123
  • Tracing the Radio/X-ray Connection in the Enigmatic Changing-look AGN 1ES 1927+654
  • Does M82 Remnant 41.95+57.5 Harbour a Central Late-stage GRB Nebula?
  • NGC 4438: Unveiling the connection between the radio shell-like structure and the ionised outflow
  • A new window on radio AGN with e-MERLIN, EVN and LOFAR
  • High-resolution observations of short GRBs beyond the LIGO horizon
  • Continued eMERLIN monitoring of ZTF22aaajecp/AT2022cmc: the first jetted tidal disruption event in a decade
  • ToO observations of the nearest recurrent nova, T Corona Borealis, during its imminent outburst

Setting up for SETI with e-MERLIN

June 2023

Searching for SETI calibrator sources resulted in a neutral hydrogen detection but no technosignatures.

Over the course of the last decade, the Breakthrough Listen project has reinvigorated the search for extraterrestrial intelligence (SETI) to buy telescope time and develop new tools and techniques. Until recently, large single dishes have been used e.g. the Robert C. Byrd Green Bank Telescope (GBT) as well as beam-forming arrays e.g. the MeerKAT that forms pencil-shaped beams for targeted searches over a small area of the sky. The use of arrays with long baselines like the European VLBI Network (EVN) has not been fully explored despite the advantages such arrays offer over the other instruments. VLBI arrays are more robust to radio frequency interference since RFI must be present in a baseline to correlate. The increased sensitivity increases the robustness of the detection and VLBI has a high astrometric accuracy which could aid in the localisation of technosignatures in the solar system.

University of Manchester Phd student Kelvin Wandia and collaborators set up a VLBI experiment to search for secondary calibrator sources for future SETI surveys in the Kepler fields, which include Kepler-111b, an exoplanet orbiting a G-type star. While no secondary calibrators were found, a nearby primary calibrator, J1926+4441 was correlated at high temporal and spectral resolution in order to search for SETI-like signals. During the data analysis, a feature at 1420.4 MHz was found, though further follow-up observations with the EVN and e-MERLIN revealed that the feature was due to the rise in the system temperatures due to galactic hydrogen filling the beams of the antennas. However, this still demonstrated a new data analysis/interpretation scheme for SETI using VLBI. After flagging this feature from the data, it was possible to search for technosignatures from Kepler-111b, though no transmitters were detected.

Read the full article here.

YERAC's coming to Manchester

June 2023

The University of Manchester and e-MERLIN will host the 52nd Young European Radio Astronomers Conference from 12 - 15 September 2023.

The Young European Radio Astronomers Conference (YERAC) has been running since 1968, giving early career researchers from across Europe an opportunity to meet and present their research to their peers. The relaxed atmosphere provides a welcoming introduction to conferences. This will be the sixth time that the University of Manchester/Jodrell Bank has hosted YERAC. Up to 40 participants will be joining us from 12-15 September 2023.

Find out more about YERAC 2023 session here.

The first radio detection of a Type 1a supernova, thanks to e-MERLIN

May 2023

SN2020eyj was detected in the radio using e-MERLIN, over 500 days after the initial optical discovery

Supernovae are the result of the deaths of stars - a large explosion rips the star apart. They are responsible for some of the heavier elements we find in the Universe. One of the best studied types of supernova are the Type 1a, which is caused by a white dwarf accreting too much mass and exploding. Because Type 1a supernovae reach the same critical mass before exploding, they have been used for years as standardisable candles in cosmology. However, two competing mechanisms have been argued to be the progenitor systems of Type 1as, either the merger of two white dwarfs, or, one white dwarf accretes mass from a companion normal star. Detecting radio emission from a Type 1a supernova has long been sought after, as it is expected in the case of accretion from a companion star, but not if two white dwarfs merge.

The Type 1a supernova SN 2020eyj exploded in March 2020 and was followed by the optical community. It was realised from late-time optical spectra that SN 2020eyj was a sub-type of Type 1a supernova which showed signs of circumstellar medium interaction and was re-classified as a Type 1a-CSM supernova. Following this discovery, requests were made to e-MERLIN to observe this potentially interesting source, over 500 days from its initial discovery.

e-MERLIN's unique combination of sub-arcsecond resolution and micro Jansky sensitivity enabled the detection of SN 2020eyj, the first ever for any Type 1a supernova. The detection of the radio emission in this source effectively rules out the white dwarf merger scenario for SN 2020eyj. This discovery of late-time radio emission from a Type 1a supernova will guide and shape future studies with the next generation of instruments like the Square Kilometre Array.

Read the Manchester press release here.

Read the full article here.


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