Description
Organisers: Eva Duran Camacho, Rebecca Houghton, Elizabeth Watkins; co organisers: Helena Faustino Vieira, Rowan Smith, Thomas Williams
Star formation (SF) is a fundamental process in the Universe, driving processes from the chemical and physical evolution of galaxies down to the initial conditions for planet formation. Local star forming processes, such as stellar feedback, and the larger galactic environment self-interact, altering star-forming conditions within individual molecular clouds and within galaxies globally. However, we still do not have a complete picture of SF across different scales and environments, from both observational and theoretical perspectives.
During this session, we will aim to:
o Link SF studies across different physical scales and environments (i.e. spiral arms, inter arms, galactic centres, and outer galactic regions).
o Improve cross-disciplinary discussions and encourage collaboration between observers and theorists.
The session will be divided into two blocks. The first block will explore resolved SF within individual molecular clouds and their connections to their galactic environment. The second block will provide insights on how galaxy evolution and galaxy-scale structures impact molecular cloud properties and SF within. Each block will consist of a 75-minute series of talks (1 review and ~4-5 contributed), followed by a 15-minute discussion on open questions in the field and how to address them, from both an observational and theoretical standpoint.
With facilities such as JCMT, ALMA, and JWST providing a wealth of new information both in the Milky Way and in nearby galaxies, this session will share the latest results across the star formation community and facilitate discussions between both simulators and observers working across different scales and environments.
Star formation is modified in molecular clouds by feedback from young massive stars. Pre-supernova feedback mechanisms are particularly important as they will set the stage for supernovae and the dispersal of energy out into the wider galactic environment, thus altering galaxy evolution. I describe how star formation and feedback can depend on galactic environment, for example for different...
Recent advancements in instrumentation have enabled the investigation of star-forming regions in nearby galaxies with unprecedented spatial resolution. To facilitate detailed comparisons between simulations and observations, we generate mock emission line maps based on a state-of-the-art simulation of an ideal H II region, utilizing a novel post-processing pipeline. This simulation couples...
We examine the connection between diffuse ionized gas (DIG), HII regions, and field O and B stars in the nearby spiral M101 and its dwarf companion NGC 5474 using ultra-deep Hฮฑ narrow-band imaging and archival GALEX UV imaging. We find a strong correlation between DIG Hฮฑ surface brightness and the incident ionizing flux leaked from the nearby HII regions, which we reproduce well using simple...
Recent observational studies find that the star formation efficiency (SFE) per free-fall time varies both within and between galaxies. This strongly implies that galactic star formation (SF) might have additional physical dependencies beyond that on the gas mass/density implied by the Schmidt-Kennicutt relation. Yet this relation is often used to model SF in (cosmological-scale) simulations,...
Arp220 is the nearest and brightest ultraluminous infrared galaxy and thus represents an ideal laboratory for studies of star formation in the extreme environment of a massive galaxy merger. Arp220, in particular, hosts star formation at a rate of ~100 solar masses per year, most of which takes place in heavily obscured molecular disks around the nuclei of the two merging galaxies. We here...
The Milky Way's Central Molecular Zone (CMZ) is a unique laboratory for studying astrophysical processes in an environment that is more extreme than typical star-forming regions in the Galactic disk. To understand the complex interplay between Galactic-scale processes and the small-scale physics of star formation, we have observed the entire CMZ as part of the ALMA Large Program 'ACES' (ALMA...
The Milky Way's central molecular zone (CMZ) presents an extreme environment for star formation, hosting the nearest supermassive black hole, young star clusters, and dense molecular gas clouds. Despite this rich environment, the CMZ perplexes astronomers by producing fewer stars than expected based on dense gas scaling relations. The ALMA CMZ Exploration Survey (ACES) aims to address this...
Accurately determining the properties of the Central Molecular Zone (CMZ) poses a complex challenge for astronomers due to significant contamination from the Galactic Spiral Arms, through which we observe.
In position-velocity space, the CMZ is characterised by high-velocity spatially compact signals, while the Spiral Arms show low-velocity spatial extended signals. Considering this, we...
The BISTRO (B-fields in Star-Forming Region Observations) Survey, a JCMT Large Program mapping Galactic star-forming regions with the POL-2 polarimeter, has constructed the largest extant sample of magnetic fields in star-forming region observed at sub-arc minute resolution. I will present a range of recent results from the survey, showing the similarities and differences between magnetic...
The inner 100โฏpc of the Central Molecular Zone (CMZ) of the Milky Way is characterized by extreme conditionsโhigh gas densities, vigorous turbulence, and strong magnetic fieldsโthat differ markedly from those in the Galactic disc. Yet, despite this abundance of dense gas, the star formation rate is observed to be roughly a factor of two lower than that in the disc, which is a long-standing...
Protostellar jets play a pivotal role in injecting matter and momentum into their environment, influencing regions several parsecs in size. This feedback mechanism significantly impacts the dynamics, morphology, and fragmentation of molecular clouds, which in turn, affects the formation of subsequent protostars. Understanding how jets regulate accretion processes and filamentary structures is...
Understanding the interplay between galactic dynamics, star formation, and stellar feedback is crucial for constructing a comprehensive model of star formation. To explore how the large-scale environment affects local star formation, we simulate an isolated star-forming galaxy and zoom into different regions to characterise how star formation varies in relation to bulk properties.
The galaxy...
Galaxies experienced a critical phase of rapid evolution 8โ10 billion years ago (Cosmic Noon), shaping the morphological types seen in the local Universe, with characteristic features like bulges and spirals. However, direct imaging of these substructures in formation was not possible before JWST. I will present a series of works where we exploit JWST/NIRCam and ALMA images to fully...
Star formation driven outflows play an important role regulating the gas supply of galaxies, thus regulating the star formation. However, we still need a consensus on the details of this feedback process, particularly in starbursting environments. I will present results from the DUVET sample of local starbursting galaxies observed using the IFU KCWI/Keck. We measure ionised gas outflows in...
Galactic environment is thought to be one of the key factors in driving the cosmic quenching of star formation in galaxies. The Fornax cluster is a nearby intermediate-mass cluster that is more representative of the clusters found in the Universe compared to other nearby clusters such as Virgo and Coma. Recent deep optical and radio observations (with VST and MeerKAT) revealed several...
A recent JWST near-infrared picture of part of the Ophiuchus star-forming region, Ophiuchus A, using the NIRCAM instrument at 1-5 microns, shows more detailed structure in this region than has ever been seen before in a single image. We use this image to further interpret our results from the B-fields in Star-forming Region Observations (BISTRO) Survey using submm polarization data taken with...
North PHASE survey is a 5 year survey that will be using time-resolved, large field data, to unveil structures and processes in young stars (YSO) at the relevant scales for inner planet formation, while also studying the connection between stars, their formation history, and their clusters, independently of astrometry.
Studying young star cluster Trumpler 37 (Tr37) provides key insights...
Gravity, turbulence, and magnetic fields are thought to be the three main factors influencing star formation. In Peretto et al. 2023 the gravity and turbulence in a sample of star-forming clumps and their parent molecular clouds were investigated. The findings of this study were that clumps are dynamically decoupled from their parent molecular clouds - this result might indicate that the star...
Ices in molecular clouds play a key role in star and subsequent planet formation. One of the leading questions in this field of research is how the chemical complexity and abundance of ice species vary across different molecular clouds and at different stages of the star formation process. Addressing this will help to understand the solid-state molecular budget of key elements such as carbon,...
In this talk, I will present a first-of-its-kind map of Star Formation Efficiency (SFE) across a high-redshift galaxy. SFE is defined as the star formation rate (SFR) divided by the total gas mass of the ISM, computed per unit area (i.e., SFE =ย ฮฃ_SFR/ ฮฃ_Mgas). SDP81, located at z = 3.042, is an ideal candidate for this study because the magnification from gravitational lensing allows us to...
In the nearby universe, the process of star formation, deeply embedded in molecular clouds, seems to be remarkably similar regardless of where we look. Perhaps once gravity takes over, this process is insensitive to the conditions under which a given cloud was formed or how it evolved, making star formation effectively universal. Nevertheless, we see growing evidence that the process of...
The formation of massive stars is a violent, explosive process. Even before the start of the main sequence, massive stars can significantly alter their environments through HII regions and outflows that can reshape the surrounding gas and dust in the host molecular clouds. This can have consequences for future star formation in proximity to these early-type stars, potentially even leading to...
The Magellanic Clouds are two nearby, gas-rich, and metal-poor galaxies, characterised by extended regions of star formation (SF). Thanks to their proximity, they represent ideal targets for the study of resolved star-formation processes in a metal-poor environment.
For this work we analysed near-infrared data obtained with the VISTA Survey of the Magellanic Clouds (VMC, Cioni et al. 2011) on...
Dust obscured galaxies, such as those selected at submillimetre wavelengths, represent a population of strongly star-forming galaxies at $z \sim $1-4, which have been empirically claimed to have many properties expected for the progenitors of local spheroidal galaxies. It is unclear whether dusty galaxies are predominantly turbulent merger-driven systems like local ultra-luminous infrared...
The SEDIGISM survey reveals properties of molecular clouds located in a range of environments across our Galaxy. Here we show our analysis on the kinematical properties of such molecular clouds, using the 13CO$(2-1)$ line emission. By analysing the light from this emission, we are studying whether clouds from different environments have different preferred direction of rotation compared to...
We present observations of the massive star-forming region IRAS 16562โ3959 observed with ALMA Band 6 as part of the Magnetic Fields in Massive Star-forming Regions (MagMaR) project. IRAS 16562โ3959 is an incredibly complex region with a dust ring cavity surrounding the massive protostar driving multiple outflows including a radio jet and massive outflow observed by Hubble. There are multiple...
Giant star-forming clumps (GSFCs) are areas of intensive star-formation that are commonly observed in high-redshift (z > 1) galaxies. Observations of low-redshift clumpy galaxy analogues are rare but the availability of wide-field galaxy survey data makes the detection of large clumpy galaxy samples much more feasible. We present a population of ~20,000 clumps in ~16,000 galaxies at redshifts...
The evolution of galaxy sizes allows us to constrain galaxy formation models. Crucially, JWST now provides the ability to observe the build-up of galaxies at the Epoch of Reionisation (EoR) in the rest-frame optical, granting the ability to observe the impacts of the first episode(s) of star formation on galaxy sizes. We analyse the sizes of H$\alpha$-selected star-forming galaxies at z = 6.1...
In recent decades, the modelling of increasingly high quality photometry and spectroscopy have led to significant progress in understanding galaxy formation and evolution up to early cosmic epochs. The resolving of the data into sub-kpc scales within galaxies is expected to incur further advances. We present a new hierarchical Bayesian SED fitting method that fits data from all pixels in...
Our understanding of star and planet formation primarily comes from studies of local molecular clouds. However, the environmental conditions in local star-forming regions vary significantly from those in the Galactic Centre. The Central Molecular Zone (CMZ) is the innermost few-hundred parsecs of the Galaxy, and the dense gas fraction, temperature, magnetic field strength, and gas pressure in...
Molecular clouds are stellar nurseries, vast clouds of dense dust and gas in which stars and their associated planetary systems form. Instabilities within the cloud manifest in the creation of localised cores of higher density, the interiors of which are under conditions favourable to the ubiquitous formation of icy mantles on dust grain surfaces. The main carbon isotope $^{12}\textrm{C}$ and...
The densities of young star-forming regions vary by several orders of magnitude, and it is currently unclear if this is the outcome of star formation, or a dynamical evolution effect. It is crucial that we investigate the long-term evolution of star-forming regions with a range of densities, as the density determines whether young stars (and their planetary systems) are much more likely to...
To understand the influence of magnetic fields on star formation processes, we estimated the magnetic field strength in IC348, L1448, L1455, NGC1333, and B1 of the Perseus molecular cloud using the Davis-Chandrasekhar-Fermi (DCF) method and its modified approaches. The angular dispersion was derived from 850 $\mu$m polarization data observed by the JCMT, while velocity dispersion was measured...
The cosmic era between 1<z<2, the so-called โcosmic noonโ, marks the peak of cosmic star formation, during which a large fraction of present-day stars has been formed. At these redshifts, typical star-forming galaxies are clumpy, gas-rich discs with high levels of turbulence and star formation activity. However, the mechanisms regulating star formation at these early epochs remain poorly...
Understanding the interplay of dust in the galactic environment is crucial to gaining insight for the many chemical and physical processes a galaxy may undergo over its evolution. Dust grains are ever present in the ISM, shaping star formation via cooling gas clouds or absorbing and then re-emitting energy from its host in the sub-mm wavelengths. For most Early-Type galaxies (ETGs)...
Whilst the evolutionary pathways of low-mass star formation have been largely well-understood, their counterparts towards the high-mass end is not and remain open for investigations still. The magnetic fields (B-fields) around giant molecular clouds are one of many key factors affecting the processes of massive star formation. Their structures and properties can be probed through polarised...
Dust in the ISM plays a crucial role in various astrophysical processes: it acts as a coolant in star-forming regions, facilitates molecular hydrogen formation, and influences star formation. Additionally, dust traces ISM content and chemical evolution of galaxies. We have recently discovered that dust properties vary significantly within galaxies, exhibiting radial gradients, highlighting the...
Large datasets are becoming increasingly common in astronomy, with LSST Rubin and Euclid, poised to release an immense wealth of data. To process this data, astronomers have developed tools such as outlier detection algorithms to probe for novel detections and information. In this presentation, we utilise an unsupervised machine learning model, an Isolation Forest (IF), to pinpoint outlying...
Time-resolved data is a powerful tool to investigate spatial scales well beyond the range of direct imaging and โusing time to map spaceโ is the only feasible method to study small-scale processes and structures, for a statistically significant numbers of sources. I will present my study of time variability, in the spectroscopy and photometry, of young intermediate-mass stars comprising of...
