Netherlands Astronomers' Conference 2024

Session

Plenary session

May 13, 2024, 1:00 PM

Lamoraalzaal

73. Opening by Nathalie Degenaar, Mitchel Stoop & Peter Barthel

5/13/24, 1:00 PM

1. Invited "meet-new-staff": Internal fractionation of atmospheric volatiles on molten exoplanets

Tim Lichtenberg

5/13/24, 1:15 PM

Low-mass exoplanets in a fully to partially molten state open a novel window into key processes that shape the earliest, high-temperature evolutionary regimes of rocky worlds and their long-lived climate states. I will outline how magma ocean dynamics and core-mantle chemical segregation influence the feedback mechanisms between largely molten interiors and volatile envelopes. The physical and...

2. Tidal disruption events’ constraints on the origin of massive black holes

Anna Balaudo

5/13/24, 1:30 PM

Observed rates of Tidal Disruption Events (TDEs) can be used to probe the mass function of intermediate mass and massive black holes (MBHs), which in turn contains crucial information on the origin and evolution of these objects. In our latest work, we use semi-analytical codes of galaxy formation - encompassing different astrophysical models of MBH formation and growth - to obtain the rates...

3. A NICER View of the Nearest and Brightest Millisecond Pulsar: PSR J0437−4715

Devarshi Choudhury

5/13/24, 1:45 PM

Neutron stars provide a unique laboratory for probing the nature of ultra-dense matter in the universe. NICER, the Neutron Star Interior Composition Explorer is a NASA X-ray telescope aboard the International Space Station designed for Pulse Profile Modeling (PPM) of rotation-powered Millisecond Pulsars (MSPs). Leveraging NICER’s megasecond exposures, large effective collecting area, and high...

4. Perceptions of the societal responsibility of astronomers in the context of the Africa Millimeter Telescope

Maaike Pierik

5/13/24, 2:00 PM

In recent years, astronomers are increasingly urged by policy makers and funders to anticipate the societal impact of their research by engaging in early-stage dialogues with society. In addition, recent citizen protests around astronomical facilities have stirred up discussion on the societal responsibility of astronomers. Most prominently, this was visible around the Mauna Kea Observatories...

30. Euclid in space!

Koen Kuijken

5/13/24, 2:15 PM

Euclid was launched on July 1st 2023. It is ESA's latest cosmology mission: a wide field optical+near-IR imager that will map almost 15000 square degrees of extragalactic sky for studding the large-scale structure of the Universe. The first six months of commissioning were exciting, and I will present some of the adventures we encountered as well as discuss the status of the survey so far.

6. Invited "meet-new-staff": Radio detection of high energy cosmic particles

Katharine Mulrey

5/13/24, 3:00 PM

Hi everyone! I am Katie Mulrey and I started as an assistant professor at Radboud in August 2021. My research interests focus on the radio detection of high energy cosmic particles, especially cosmic rays and neutrinos. I use radio telescopes like LOFAR (and in the future SKA) to map out the radio footprint of cosmic-ray events and understand their origin. I also work on building in-ice...

7. Mass loss from massive stars as function of metallicity

Frank Backs

5/13/24, 3:15 PM

Massive stars have significant effects on their surroundings, they do this through ionizing stellar radiation, mechanical feedback from stellar winds, and energetic supernova explosions. In these processes they shape galaxies and enrich their chemistry with metals and the building blocks for life. The stellar winds also significantly affect the stars themselves. During their relatively short...

8. Dutch astronomy during the climate crisis

Violette Impelizzeri

5/13/24, 3:30 PM

The climate emergency is already here and it is happening faster than anyone expected. This means that not only nations need to consider urgent mitigating policies - with UN and EU regulations now mandating a reduction of emissions by 55% in 2030 - but that we all need to become part of a solution. As such, at institutional level, we should also feel empowered to address this global problem,...

9. Spectral Stacking of MHONGOOSE Data - Searching for Neutral Hydrogen Clouds in the Cosmic Web

Simone Veronese

5/13/24, 3:45 PM

The investigation of the large-scale distribution of neutral hydrogen (HI) within the cosmic web is fundamental in comprehending the intricate processes governing galaxy formation and evolution. Evidently, the star formation rate observed throughout cosmic history necessitates galaxies to continually replenish their gas reservoir. Theoretical simulations predict that this replenishment...

10. The MeerKAT single-pulse census of the pulsar population: What do 1.6 million pulsar pulses tell us?

Xiaoxi Song

5/13/24, 4:00 PM

Single pulses of pulsars show a wealth of phenomena, e.g. drifting subpulses where subpulses systematically march in pulse phase. Such single pulse phenomena are revealed with unprecedented details by using highly sensitive and long enough observations. In addition, the evolution of drifting subpulses across the pulsar population can be studied with large survey projects. These provide crucial...

11. Invited "meet-new-staff": Teaching astronomy

Marcel van Daalen

5/13/24, 4:15 PM

Both as staff and as students, we are all involved in teaching – yet we rarely discuss it, particularly across institutes. During these 15 minutes, we take a first step towards changing this. I will briefly present some best practices in teaching astronomy, before we open the discussion to the room and talk about how to educate effectively, both from the lecturer and the student perspective.

12. Invited "meet-new-staff": XRISM early results and scientific impacts

Liyi Gu

5/14/24, 1:30 PM

In September 2023, the XRISM X-ray mission was successfully launched. It is built upon a major collaborative effort between Japan and US, with significant participation from Europe including the Netherlands. In this talk I will show its first light observations and early-releasing data, providing insight into revolutionary scientific breakthroughs that promise to reshape the landscape of X-ray...

13. Witnessing radiatively-driven ionised outflows in active galactic nuclei

Anna Juranova

5/14/24, 1:45 PM

Most active galactic nuclei show outflows of ionised gas, but the driving force behind their acceleration is rarely identified, hindering our understanding of the complex processes at play. Here, we present new insights into the outflows of I Zw 1, a nearby quasar-like galaxy. From multi-wavelength spectra, we identify line-driving as an important mechanism propelling the ionised gas. The rich...

14. The properties of pre-main sequence stars in the massive Galactic star formation region NGC 3603 with JWST NIRSpec.

Ciaran Rogers

5/14/24, 2:00 PM

The majority of stars form in clusters that contain at least one massive star. Massive stars dominate the radiation field and dynamics of the cluster, but the exact impact they have on star formation is unclear. We have obtained JWST NIRSpec spectra of 100 stars in the massive Galactic star forming region NGC 3603 using the micro shutter array in high resolution mode. The targets consist of...

15. Weighing Herbig disks: Obtaining gas and dust masses of Herbig disks using millimeter interferometer observations

Lucas Stapper

5/14/24, 2:15 PM

In the past decade many population studies have been performed with the Atacama Large Millimeter/submillimeter Array (ALMA) to understand the bulk properties of planet-forming disks around young stars. These population studies mostly consist of late spectral type (i.e., G, K & M) stars, with relatively few intermediate mass Herbig stars (spectral types B, A, F). With GAIA updated distances,...

62. Results and recommendations from the work climate survey

Ilse van Bemmel

5/14/24, 2:30 PM

At the start of 2024 the first ever Dutch astronomy work climate survey was held. This was initiated in 2023 by the Astronomy Round Table, NAIEC and the Astronomy Council, and executed by Ipsos. After the analysis by Ipsos the NAEIC survey team has been developing a set of recommendations, in collaboration with the local Equity and Inclusion committees. In this presentation I will present the...

17. Invited "meet-new-staff": The first inroads into the low-frequency gravitational wave spectrum

Aditya Parthasarathy

5/15/24, 9:00 AM

Supermassive black holes at the centres of merging galaxies are expected to form binary systems whose orbital motion generates gravitational waves. A cosmological population of such systems combine to build up a gravitational wave background (GWB). A significant detection of this GWB will provide the first stringent constraints on the dynamical evolution of supermassive black holes and their...

18. Unveiling the structure of the Jhelum stream with ant colony-inspired computation

Petra Awad

5/15/24, 9:15 AM

The halo of the Milky Way galaxy hosts multiple dynamically coherent substructures known as stellar streams that are remnants of tidally disrupted orbiting systems such as globular clusters (GCs) and dwarf galaxies (DGs). A particular case is that of the Jhelum stream, which is known for its unusual and complex morphology. Using the available data from the Gaia DR3 catalog, we extracted a...

19. Search for a spectral cut-off and periodic signal from a radio brown dwarf binary

Timothy Wing Hei Yiu

5/15/24, 9:30 AM

Brown dwarfs display Jovian auroral phenomena such as coherent radio emission, which is a probe of magnetospheric acceleration mechanisms and allows us to directly measure the emitter’s magnetic field strength. Radio observations of the coldest brown dwarf are particularly interesting since their magnetospheric phenomena may be very similar to those in gas-giant exoplanets. Here, we present...

20. A periodic radio transient found with LOFAR

Iris de Ruiter

5/15/24, 9:45 AM

In this talk, I will discuss a new radio transient that we found in a commensal transient search of the LOFAR survey data (de Ruiter et al. 2023, submitted). The source has shown several bright minute-duration radio flares with a periodicity of two hours. Long-period radio transients are an emerging class of extreme astrophysical events of which currently only three are known (Caleb et al....

21. Invited "meet-new-staff": The need for ab initio and laboratory simulations in exoplanet science

Kaustubh Hakim

5/15/24, 10:00 AM

Mass-radius measurements of exoplanets over three decades have revealed three major classes based on bulk composition. This decade is witnessing a significant shift from the atmospheric characterisation of gas giant exoplanets to their smaller counterparts, sub-Neptunes and rocky exoplanets. While the observations of atmospheres of sub-Neptunes and rocky exoplanets keep growing, the...

22. Invited "meet-new-staff": The polydisperse nature of Planet Formation

Sijme-Jan Paardekooper

5/15/24, 11:00 AM

Planets form in discs of gas and dust around young stars. Within these discs, solid particles have to grow 12 orders of magnitude to form terrestrial planets. This process is never going to be 100 percent efficient at all times, so that there will always be a distribution of sizes in solids. The dynamics of a mixture of dust sizes, coupled to the gas through friction, can be complex and...

23. GRMHD simulations of accreting neutron stars

Pushpita Das

5/15/24, 11:15 AM

Numerical modeling of accreting millisecond X-ray pulsars (AMXPs) allows us to understand the physical origin of different observational signatures detected from these systems. Since the birth sites of these signals are strongly affected by the gravitational potential of the star, magnetohydrodynamic (MHD) simulations in full GR (GRMHD) are essential to accurately capture space-time curvature...

24. Dynamics of disk galaxies: what causes the spirals?

Sven de Rijcke

5/15/24, 11:30 AM

As young children explore the world around them, they quickly discover that a lot can be learned about a complex system by gently poking it and observing how it reacts to that. Astronomers who are interested in the internal workings of disk galaxies, such as our Milky Way, also follow this approach. In this case, nature does the poking for us. The stellar and gaseous disks of galaxies are...

25. Mg abundance of the globular cluster NGC2419 using WEAVE

Mariya Nizovkina

5/15/24, 11:45 AM

Chemical abundances of globular clusters (GCs) are a powerful tool to investigate the history of their and their host galaxy’s formation. These can be measured with integrated-light (IL) spectroscopy with a precision of 0.01 dex. However, the abundances of Mg in the spectra of the Milky Way (MW) and extragalactic GCs show deviation compared to the abundances of alpha-elements. These anomalies...

26. Dust destruction by supernova blast waves in a turbulent interstellar medium

Tassilo Scheffler

5/15/24, 12:00 PM

Core-collapse supernovae are one of the main producers of cosmic dust. Their remnants incorporate the perfect conditions for molecules to grow to dust grains, starting from a few hundred days after the explosion. However, the produced 0.01 to 1 solar masses of dust per supernova will eventually encounter the energetic reverse shock, while an even larger amount of pre-existing interstellar dust...

27. Invited "meet-new-staff": Unveiling the photochemical evolution of carbonaceous molecules: experimental and theoretical studies.

Alessandra Candian

5/15/24, 12:15 PM

The new stunning observations delivered by the James Webb Space Telescope are revolutionizing our view of the molecular universe, in particular when it comes to large carbon-containing species such as Polycyclic Aromatic Hydrocarbons (PAHs) and carbon cages. The JWST infrared spectra show a treasure of spectroscopic features that change in response to the physical conditions in the...