Extra seminars, which can be organised by anyone in the group separately from the colloquium series, are also included on this page for convenience.
To view a talk abstract, click on the talk title. Click again on the talk title to hide the abstract.
| Date | Speaker | Topic |
|---|
| Sep 27 |
Premana Premadi, Hesti Wulandari, Taufiq Hidayat, Mahasena Putra
(Institut Teknologi Bandung, Indonesia) |
Some Highlights of Astronomy Research in Indonesia |
| Dr. Premadi will talk about on-going studies on galaxy evolution parameter using optical data and on the effect of gravitational lensing on cosmological parameter estimation.
Dr. Wulandari will talk about cosmology with galaxy clusters, focusing on study of galaxy clusters as standard bucket using Chandra X-Ray satellite data.
Dr. Hidayat will talk about cooperation projects using ALMA. We work on the chemistry and dynamics of Titan's atmosphere using ALMA, particularly from observations of several molecules and its isotopologues: CO (plus 13 CO and C 18 O), HCN (plus DCN, H 13 CN, and HC 15 N), HNC, CH 3 CN, CH 3 CCH, C 2 H 5 CN, and HC 3 N. (Cooperation with R. Moreno, Paris Observatory, and Mark A. Gurwell, CfA Harvard). We also use ALMA calibrators to make continuum deep-field images in several ALMA bands (3, 6, and 7) to study the environment of radio galaxies. (Cooperation with Stephane Leon and Baltasar Vila-Vilaro, Join ALMA Observatory, Santiago), also for joint supervision of Ph.D thesis.
Dr. Putra will talk about one particular research at the Bosscha Observatory, namely CCD observation of daylight crescent moon. This technique is developed to determine the first day of each lunar calendar month, which is of great importance in Islamic community.
Host: Rene Breton |
| Oct 11 |
Schuster Colloquium - Dr Samaya Nissanke
(Radboud University, The Netherlands) |
Clash of the Titans: New Astrophysics of Binary Black Holes from LIGO's First Observations |
| From September 12 2015 to January 19 2016, the first observational run of the Advanced LIGO detectors saw the first detections of gravitational waves from binary black holes. In this talk, I will first discuss how to infer and characterise the fundamental properties of the black hole systems. I will then present the tests of general relativity and the implications for astrophysics that are made possible from these measurements. With these gravitational wave detections in hand, I conclude with the unprecedented opportunities and challenges that are opening up in strong-field gravity astrophysics during the next decade.
Hosts: Jens Chluba and Rene Breton |
| Oct 18 |
Susanne Aalto
(Chalmers University of Technology, Sweden) |
Molecular outflows in AGNs and starbursts |
| Cold gas plays a central role in feeding and regulating star formation and growth of supermassive black holes (SMBH) in galaxy nuclei. Particularly powerful activity occurs when interactions of gas-rich galaxies funnel large amounts of gas and dust into nuclei of luminous and ultra luminous infrared galaxies (LIRGs/ULIRGs). These dusty objects are of key importance to galaxy mass assembly over cosmic time.
It is also increasingly clear that feedback from star formation and AGNs is fundamental to regulating the evolution of galaxies in the nearby Universe as well as at earlier epochs. Mechanical feedback occurs in the form of winds (stellar, AGN, galactic), turbulence, supernova bubbles and superbubbles, AGN jets and backflows. There is mounting evidence that massive amount of cold molecular gas is being expelled from galaxy nuclei and starburst regions by the feedback process. With the advent of ALMA and the NOEMA telescopes we can now study the extent, morphology, velocity structure, physical conditions and even chemistry of these cold flows at unprecedented sensitivity and resolution.
I will focus on recent ALMA and NOEMA studies of AGN and starburst outflows from dusty galaxies. In particular I will, for example, present recent ALMA studies with resolutions of 30 milli arcseconds (5 - 7 pc) of the launch regions of molecular outflows and jets in the nearby LIRGs NGC1377 and IC860. These outflows different in nature where NGC1377 shows a 150 pc scale radio-quiet molecular jet that appears to be precessing -- while the IC860 flow is exceedingly compact and dense and appears to be in a young phase. I will also show the importance of JVLA and MERLIN observations for matching high-resolution continuum (and even molecular) studies of nuclear outflows. Finally, I will give the ALMA view of a double-jet from the starburst galaxy NGC3256.
Host: Rob Beswick |
| Oct 25 |
Michael Shara
(American Museum of Natural History, New York) |
Novae and Supernovae: Intimate Connections |
| Classical novae and supernovae were long thought to be completely separate astrophysical phenomena. This is no longer true; most type Ia supernovae (SNIa), the "standardizable candles" that led to the discovery of the dark energy, are now understood to have had symbiotic nova progenitors. Symbiotic novae consist of a red giant and a rapidly accreting, frequently erupting white dwarf. Some of the offspring of these binaries are close double white dwarfs, which are equally viable SNIa progenitors. Understanding the evolution of these binaries over a Hubble time is essential to a robust calibration of the crucial standard candles that they produce.
I'll review the current state of knowledge of the short and long-term temporal evolution of the white dwarfs in novae, and predictions about how these can lead to SNIa. A test of a key prediction of the theory is underway. In 2017 the Hubble Space Telescope is imaging the giant elliptical galaxy M87 53 times - every 5 days over 9 months - in a search for recurring "ultraviolet flashers" in M87. These are the symbiotic novae predicted to produce SNIa. I'll present early results from this program, which should finally quantify the fractions of SNIa progenitors containing one and two white dwarfs at redshift zero. This will be a strong constraint on all evolutionary models of the binaries which produce SNIa. |
| Nov 1 |
Alessandro Melchiorri
(Sapienza Universita Di Roma, Italy) |
A crisis in lalalambda land? |
| After 100 years from its introduction current cosmological data are confirming the presence of a cosmological constant, lambda, in a spectacular way. This is the "earworm" song playing in the head of cosmologists today. But is this true ? In this talk I will illustrate some of the tensions that are now arising between cosmological observations arguing that something more tricky than a constant could be in place.
Host: Richard Battye |
| Nov 22 |
Kunal Mooley
(Oxford University) |
The First EM Counterpart of a Gravitational Wave Event |
| On 17 Aug 2017, the scientific community witnessed the birth of multi-messenger astronomy. The Advanced LIGO and Advanced VIRGO observatories detected a gravitational wave signal, GW170817, from the inspiral and merger of two neutron stars, and within 24 hours an electromagnetic counterpart was detected at gamma-ray, ultraviolet and optical wavelengths. The merger was localized to spiral galaxy NGC 4993 at a distance of about 40 Mpc. The gamma-rays recorded a faint short burst, while the optical and ultraviolet recorded the first definite detection of a kilonova. The X-rays and radio signals were detected 15 days after the merger, providing further insights into the neutron-rich relativistic ejecta and the environment. In this talk I will describe the multi-messenger search and the rich astrophysics that was (and is still being) uncovered from this historic gravitational wave event.
Host: Rob Beswick, Charlie Walker |
| Nov 29 |
Emily Drabek-Maunder
(Cardiff University) |
How do habitable planets form? Using submillimetre and radio telescopes to understand the origins of our Solar System |
| Within the past two decades, thousands of exoplanets have been discovered throughout our Galaxy. This sparks exciting possibilities for life outside our Solar System, where recent work suggests that 1 in 5 Sun-like stars may have an Earth-sized exoplanet in their habitable zones. However, rocky planet formation is not well understand, which is key to understanding how habitability develops on Earth-like worlds. In this talk, I'll be discussing my work using recent surveys on submillimetre and radio telescopes to address how exoplanets and planetary systems form around nearby stars, including the JCMT Gould Belt Survey (GBS) and the Planet Earth Building Blocks - a Legacy eMERLIN Survey (PEBBLeS). |
| Dec 7 |
Steven Longmore
(Liverpool John Moores University) |
The Galactic Centre: a template for understanding star formation and feedback in a high-pressure environment |
| The unknown physics of star formation and feedback represent the main bottleneck in connecting the observable galaxy population to cold dark matter cosmology. Both physical processes are expected to vary strongly with galactic environment and across cosmic history. I will discuss recent progress in understanding the physics of star formation and feedback in the inner few hundred pc of the Milky Way -- the Central Molecular Zone (CMZ) -- an environment with gas properties very similar to those in starbursts and high-z galaxies, in which most stars in the Universe formed. Within our lifetime, the CMZ is the only such environment for which it will be possible to simultaneously resolve the gas properties down to the size scales of individual (forming) stars, while also tracing galactic-scale processes, making it a critical benchmark for studies of star and planet formation, feedback, and the interstellar medium across cosmic time. I will focus on recent work seeking to explain a puzzling observational paradox: the vast majority of gas in the CMZ is underproducing stars by 1-2 orders of magnitude compared to empirical star formation relations and theoretical predictions, and yet at the same time a very small fraction of the gas is producing the most violent star formation events in the Galaxy. I will discuss the implications of these findings for environmentally (in)dependent star and planet formation relations/theories and the environment into which supernovae explode. I will finish by outlining the details of a model linking the emerging, multi-scale picture of star formation and feedback to a more general understanding of the mass flows and energy cycles in galactic nuclei.
Hosts: Gary Fuller, Rowan Smith & Naomi Asabre Frimpong |
| Dec 13 |
Lucas Lombriser
(University of Geneva) |
Cosmic Self-Acceleration from Modified Gravity before/after GW170817 |
| Scalar-tensor modifications of gravity have long been considered as an alternative explanation for the late-time accelerated expansion of our Universe. I will first show that a rigorous discrimination between acceleration from modified gravity and from a cosmological constant or dark energy was not possible with observations of the large scale structure alone. I will then demonstrate how the measurement of the cosmological speed of gravitational waves with GW170817 breaks this dark degeneracy and how the combination of the two challenges the concept of cosmic acceleration from one of the most general scalar-tensor modifications of gravity. Even more general theories, however, reintroduce the dark degeneracy and I will show how a more conclusive result will only be possible with a large number of Standard Sirens. (Refs: 1509.08458; 1602.07670; https://arstechnica.com/science/2017/02/theoretical-battle-dark-energy-vs-modified-gravity).
Host: Francesco Pace |
| Dec 20 |
Robert Minchin
(Arecibo Observatory) |
Hunting Galaxies in the Hurricane Zone |
| The Arecibo Galaxy Environment Survey (AGES) is using the Arecibo L-band Feed Array to search for and study galaxies and gas clouds in different environments using the 21-cm line of neutral hydrogen. I will discuss the results coming out of AGES, including the Virgo cluster, where we have found a population of dark clouds, M33, where we see high velocity clouds around the Triangulum galaxy, and our newest results from the Pegasus I and II clusters. I will also give an update on the recovery process at Arecibo Observatory following Hurricane Maria in September. |
| Jan 31 |
Ann Mao
(MPIfR) |
Detecting magnetic fields in distant galaxies with broadband radio polarimetry |
| Even though magnetic fields play crucial roles in galaxies from sub-parsec to kilo-parsec scales, how galaxies and their magnetic fields have co-evolved since the early universe remains an unsolved fundamental question in cosmology and astro-plasma physics due to the lack of magnetic field measurements beyond the local universe. In this talk, I will first describe how the advent of broadband radio polarimetric observations have revolutionised the field of cosmic magnetism by enabling the derivation of properties of magnetic fields in astrophysical objects that were impossible to obtain previously with narrowband data. I will then demonstrate how broadband polarimetry, in combination with innovative observational methods can allow us to, for the first time, measure magnetic fields in galaxies in previously uncharted redshift regimes. In particular, I will report our record-holder detection of micro-Gauss coherent magnetic fields in a disk galaxy as seen 4.6 Gyrs ago by taking advantage of gravitational lensing. I will conclude by discussing prospects of upcoming polarimetric surveys to be conducted with Square Kilometre Array pathfinders and the eventual Square Kilometre Array.
Host: Neal Jackson |
| Mar 7 |
Schuster Colloquium - Nigel Lockyer
(Director of Fermilab) |
Towards a New Understanding of the Quantum Universe |
| Neutrinos are the most numerous matter particles in the universe, but the least understood. The peculiar properties of neutrinos suggest connections to many of the big mysteries of particle physics, including the possibility that the matter we are made of originated from neutrinos. Today a host of new experiments are trying to unlock the secrets of these elusive particles. Fermilab is gearing up to produce a megawatt proton beam neutrino source capable of sending high energy neutrinos to giant liquid argon detectors located 1300 kilometers away and a mile underground in South Dakota. The detectors will be built and operated by a newly formed scientific collaboration called DUNE (for Deep Underground Neutrino Experiment), a global effort of over 1000 scientists, 177 universities and labs from 31 countries. DUNE will be the first truly international mega-science project hosted in the U.S., and a game-changing experiment for neutrino science. Large scientific projects with major infrastructure investments lead to breakthroughs in many areas. In this case, advances in superconducting technology needed to produce intense beams of neutrinos may also enable a big leap forward for quantum computers. |
| Mar 14 |
James Matthews
(Oxford University) |
Cosmic ray acceleration to the highest energies in powerful radio galaxies |
| The origin of ultra-high energy cosmic rays (UHECRs) is still unknown. In a related sense, the impact of CRs on the outflows that probably produce them is not well understood. The most promising CR acceleration mechanism is diffusive shock acceleration, which requires strong magnetic field amplification at the shock. Fortunately, CRs themselves can strongly amplify the magnetic field via (e.g.) the current-driven Bell instability. In this talk I will describe the theory behind DSA and present some MHD simulations of the Bell instability. I will discuss why ultra-relativistic shocks are fairly poor accelerators of UHECRs, before exploring what types of shocks are good at accelerating CRs to the highest energy. In particular, I will use hydrodynamic simulations of jets to show that back-flowing streams in the lobes of radio galaxies show moderately strong shocks (Mach numbers ~2-5), which are good candidate sites for the acceleration of UHECRs. I will briefly explore the implications for jet composition, radio galaxy populations and AGN feedback.
Host: Justin Bray |
| Mar 21 |
Aditya Rotti
(JBCA) |
Novel tools for analyzing CMB polarization maps |
| CMB polarization analysis is conventionally carried out using harmonic space methods making the definitions of E and B modes fairly obscure. In the first part of my talk, I will describe a practical real space method for evaluating the scalar E and B mode maps from Stokes parameters Q/U on the sphere. This new method elucidates the nature of E and B modes and their non-local dependence on the Stokes parameters. I will argue that it is possible to think of Stokes parameters as some complex charge, which radiates a spin-0 complex scalar field, the real part of which corresponds to E-modes and the imaginary part to the B-modes of CMB polarization. I will briefly touch upon the issue of E to B leakage due to incomplete sky coverage and how one may circumvent this issue using this real space method. In the second part of my talk, I will discuss how isotropy tests can be a powerful diagnostic for assessing foreground contamination with emphasis on the B-modes of CMB polarization maps. I will present results from our analysis carried out on Planck 353GHz polarization maps. |
| Apr 18 |
Sandy Weinreb
(CALTECH) |
Radio Astronomy Instrumentation Development at Caltech |
| Outline
1. The Owens Valley Low Frequency Array - All the sky all the time!
2. LNA Development - For quantum computing; for FRB array
3. Next Generation VLA - ngVLA
1. Introduction
2. Comparison with other radio telescope arrays
3. Cryogenics configuration to cover 1.2 to 116 GHz
4. Quadridge Flared Horn, QRFH, feed
5. Direct coupled calibration signal
6. Expected system performance
7. Prototype 1.2 to 4.2 GHz feed test data
8. Effect of feed and LNA mismatch
Host: Keith Grainge |
| Apr 25 |
Ranieri Baldi
(University of Southampton) |
The multi-band properties of low-luminosity radio galaxies in the local Universe |
| Abstract: Radio galaxies produce the most energetic phenomena in the Universe. They are typically associated with giant elliptical galaxies hosting the most massive black holes (> 10^8 solar masses). In the local Universe (z<0.3) the optical classification of radio galaxies reflects a clearer separation in nuclear and host properties than that based on the radio morphology. However, our studies show that the picture of the radio-loud AGN population provided by the classical samples of radio galaxies, i.e. 3C sample, is incomplete. Indeed, moving to low-luminosity active nuclei, the bulk of this population is dominated by objects which differ from powerful radio galaxies, by showing small radio structures and more heterogeneous host properties. However, by selecting the radio-loud low-power AGN population, a new class of radio galaxies emerges, called FR0s, which lack of large scale (>10 kpc) radio structures and dominate the local Universe in space density. Considering their properties, I will speculate about their possible origins and the possible cosmological scenarios they imply.
Host: Rob Beswick |
| May 2 |
Prof. Eiichiro Komatsu
(MPA, Garching) |
Mapping Hot Gas in the Universe using the Sunyaev-Zeldovich Effect |
| Abstract:
Hot, thermal electrons in galaxy clusters up-scatter the cosmic microwave background photons, making clusters visible in the microwave sky. This effect, known as the Sunyaev-Zeldovich effect, has been detected routinely toward individual galaxy clusters. Since the SZ effect is proportional to a projected thermal pressure of gas, we can use this effect to map all hot gas pressure in the Universe in projection. We start this talk by presenting the first image of the SZ effect obtained by ALMA, which has the highest spatial (both angular and physical) resolution ever achieved for the SZ mapping observations. With such a high resolution map comparable to X-ray maps, this SZ map enables us to study astrophysics of galaxy clusters in a new way. The second part of the talk concerns a full-sky map of the SZ effect. Thanks to its multi-frequency coverage from space, ESA's Planck satellite has produced, for the first time, a full-sky map of the SZ effect. Statistics of this map, such as one-point PDF and the power spectrum, provides a powerful test of our theory for structure formation in the Universe. Unlike gravitational lensing of the CMB, which probes structure formation of the total matter, the statistics of the SZ effect tests our understanding of baryonic structure formation on large scales. We present state-of-the-art simulation of the SZ effect, and discuss what we learned from comparing the simulation with the Planck data. In the last part of the talk, we present a new result on the cross-correlation of the hot gas map and a full-sky map of galaxy distribution from 2MASS, showing how gas traces galaxies in the local Universe.
Host: Jens Chluba |
| May 9 |
Schuster Colloquium - Dr Edward Pope
(Met Office) |
Black holes, climate change and food security |
| The global population is projected to grow to 11 billion by the end of the century, contributing to increased competition for land, water and energy resources. The climate is also changing and is likely to affect agricultural productivity, with increases in food production expected in some regions and decreases in others. The confluence of these factors represents a considerable challenge for society - how can we feed 11 billion people equitably and sustainably?
As the UK government's centre for climate research, the Met Office works to understand the impacts of both natural climate variability and climate change on human lives and livelihoods; recently, there has been growing interest in food security. The focus of this talk will be our current research assessing climate impacts on wheat, maize and rice production, which provide around 60% of the world's food energy intake. This work makes use of a 1400-member climate model ensemble to help quantify the present-day climate risk to grain production around the world, with a particular emphasis on multi-breadbasket failures which can affect global food prices. I will also discuss our work on the "human dynamics of climate change" which illustrates some of the impacts of climate and population change in the context of a globalised world - countries with high agricultural productivity often export across the world, meaning that relatively localised climate impacts, such as water stress or sea level rise, can be felt globally.
Host: Rene Breton |
| May 16 |
Morgane Fortin
(Nicolaus Copernicus Astronomical Centre, Poland) |
Neutron stars: astrophysical laboratories for nuclear physics |
| Abstract: Neutron stars are formed in supernovae during the collapse that marks the end of the life of stars with a mass of about 10 solar masses.
Although they have observed in all wavelengths for 50 years and
gravitational waves were recently detected from a binary neutron star
system, their structure and the properties of the matter inside them are
still poorly known. I will present how multi-messenger observations of
neutron stars and laboratory experiments may enable us to better
understand and constrain the properties of neutron star matter.
Host: Guillaume Voisin |
| May 23 |
Dr. Nithyanandan Thyagarajan
(NRAO) |
A novel and simplified approach to detecting structures from cosmic reionization using redshifted 21 cm experiments using bi-spectrum phase |
| Abstract Direct detection of evolving neutral Hydrogen structures from the Cosmic Dawn and Reionization Epochs (EoR) will reveal the nature of the first stars and galaxies as well as complete our understanding of a significant evolutionary phase of the Universe. Many projects such as the MWA, LOFAR, and PAPER commenced in the last decade with the promise of high significance statistical detection of the EoR, but have so far only weakly constrained models owing to underestimation of challenges from bright foreground sources and instrument systematics. These include chromatic effects from wide-field effects, antenna apertures, reflections from the mechanical and electrical interfaces in the instrument, antenna position errors, calibration errors, etc. I will describe results from my work that focuses on identifying, characterizing and providing design and analysis solutions to these various challenges which will be critical to not only enable a detection but also to place meaningful cosmological and astrophysical constraints. One of the primary limitations in analysis arises from the challenge of very high precision calibration. I will discuss a novel and a complementary approach using bi-spectrum phase that bypasses the stringent calibration requirements limiting existing approaches and could potentially improve the prospects of detecting structures during cosmic reionization. I will discuss pathways to estimating the HI brightness temperature fluctuations and its evolution with redshift in this approach.
Host: Clive Dickinson |
| May 30 |
Matt Smith
(Cardiff) |
A clean sweep for dust in Nearby Galaxies with Herschel and SCUBA-2 |
| Abstract: The Herschel Space Observatory had the largest mirror in space and with both the PACS and SPIRE instruments could observe both sides of the far-infrared dust peak. I will recap what we learnt from Herschel studies of nearby galaxies, in particular those of Andromeda, which investigated its dust properties, star-formation law, and the relationship between dust, gas and metallicity (including a search for any `dark gas' present). To make significant progress over the Herschel studies we can take advantage of new fitting techniques, as well as observations with improved resolution and wavelength coverage. I will show our latest results using PPMAP dust SED fitter (Marsh et al. 20XX), which has the advantage over previous techniques that images do not need to be convolved to the lowest common resolution, and allows for a range of temperature components. We also are leading a new large program on the JCMT (275 hour); HASHTAG will observe the entire disc of Andromeda at 850 and 450 micron. With PPMAP and HASHTAG data we will have a physical resolution of 20pc, smaller than the size of a molecular cloud, and so can investigate problems, like how the scale of the Schmidt-Kennicutt law varies with resolution. If time I will also present our work with ALMA on gravitational lensing, with targets chosen from H-ATLAS. The exquisite resolution of ALMA and the magnification from lensing, means we can now perform similar high-resolution analysis (~50pc) on high redshift systems.
Host: Adam Avison |
| Jun 6 |
Anna Watts
(University of Amsterdam) |
Bright spots on neutron stars: exploring the densest matter in the Universe |
| Densities in neutron star cores can reach up to ten times the density of a normal atomic nucleus, and the stabilising effect of gravitational confinement permits long-timescale weak interactions. This generates matter that is neutron-rich, and opens up the possibility of stable states of strange matter. Our uncertainty about the nature of matter under these conditions is encoded in the Equation of State, which can be linked to macroscopic observables like mass, radius, tidal deformation or moment of inertia. One very promising technique for measuring the EOS exploits hotspots that form on the neutron star surface due to the pulsar mechanism, accretion streams, or during thermonuclear explosions in the neutron star ocean. How the spots form is not always clear, and I will discuss some of the unsolved puzzles related to spot generation. I will then explain how the hotspot technique is being used by NICER, an X-ray telescope installed only a few months ago on the International Space Station - and why the technique is a mission driver for future large area X-ray telescope concepts such as eXTP and STROBE-X.
Host: Jens Chluba |
| Jun 13 |
Matt Browning
(Exeter) |
Convection, rotation, and magnetism in stars and planets |
| Abstract: All stars (and many planets) have magnetism somewhere in their interiors. In most cases the magnetic fields are built by the action of a dynamo, a process that converts kinetic energy to magnetic, but a comprehensive theoretical understanding of this process has remained elusive. A particular challenge is to explain how the fields come to possess the remarkable spatial or temporal organisation that is often observed, despite the presence of intense, chaotic flows and small-scale structure. Here, I will describe a series of recent results from large-scale simulations of stellar and planetary interiors, which have helped to reveal how such orderly fields might be generated amidst the turbulent convection in these objects. I will also discuss claims that strong magnetic fields, or rapid rotation alone, might affect the structure and radii of low-mass stars or gaseous planets.
Host: Jens Chluba |
| Jun 20 |
Special Seminar - Ali Mozaffari
(UCL) |
Hints of new physics in gravity and cosmology |
| Abstract: Whilst the consensus model of Lambda CDM + GR has survived many attacks over the past 30 years, recent work has laid bare the issues of inconsistent values of Lambda, the very nature of dark matter (and its detection) as well as the new field of gravitational wave cosmology brings the prospect of new and exciting ways to constrain these ideas. I will outline a few journeys in this new landscape.
Host: Daniel Thomas |
| Jun 29 |
Special Seminar - Prof. Biwei Jiang
(Beijing Normal University) |
The interstellar extinction law in the infrared |
| Abstract: With the development of infrared observation, various works are devoted to studying the interstellar extinction law in the infrared. It is found that the law differs from the prediction of the interstellar dust model which was based on the UV and optical extinction. In addition, the results show some dispersion and may imply that the extinction law is variable even in the infrared. We developed a new method to derive the extinction law more accurately in the infrared by combining the photometric and spectroscopic information of a large sample of stars. Our result is generally consistent with previous ones, while no significant variation is found in our result. A micron-sized dust component is deduced to explain the difference of the infrared extinction law with the classical dust model.
Host: Albert Zijlstra |
