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DTSTART:20230101T000000
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BEGIN:VEVENT
DTSTART;TZID=UTC:20260127T143000
DTEND;TZID=UTC:20260127T160000
DTSTAMP:20260514T162651
CREATED:20251206T080633Z
LAST-MODIFIED:20260126T111046Z
UID:6954-1769524200-1769529600@cassa.site
SUMMARY:CASSA Colloquium 13: Modelling the Last Major Merger that Shaped the Milky Way
DESCRIPTION:Speaker (in person): Istiak Akib\, PhD candidate\, Laboratoire d’Instrumentation et de Recherche en Astrophysique (LIRA)\, Observatoire de Paris\, Paris Sciences et Lettres University (PSL)\, France. \nAbstract: The last major merger of the Milky Way (MW) occurred 9-10 Gyr ago with an incoming galaxy known as the Gaia-Sausage Enceladus (GSE). We present the first hydrodynamical modelling of this collision using GIZMO. Our simulation reproduces the observed kinematic signatures of GSE. Furthermore\, the merger model successfully recovers key structural and dynamical properties of the present-day MW\, such as\, the bulge\, disk\, bar and its rotation\, four spiral arms\, surface mass density\, rotation curve\, gas fraction\, and star formation history. The simulations also show evidence for the Galactic warp and flare.
URL:https://cassa.site/event/colloquium-13/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2024/12/akib-1.webp
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20251218T143000
DTEND;TZID=UTC:20251218T160000
DTSTAMP:20260514T162651
CREATED:20251206T080700Z
LAST-MODIFIED:20251217T081001Z
UID:6952-1766068200-1766073600@cassa.site
SUMMARY:CASSA Colloquium 12: Between Stars and Planets
DESCRIPTION:Title: Between Stars and Planets: Unveiling the Hidden World of Transiting Brown Dwarfs \nSpeaker: Md Redyan Ahmed\, PhD candidate\, Sydney Institute for Astronomy (SIfA)\, University of Sydney\, Australia. \nAbstract: Transiting brown dwarfs occupy the mass range between stars and planets\, placing them in a unique regime where the physics of both worlds begin to overlap. Wide-field surveys have identified more than 1\,000 isolated brown dwarfs in the Solar neighbourhood\, yet only about 50 systems are known to transit their host stars. With the arrival of the TESS mission\, this picture has begun to change: the sample of transiting brown dwarfs is growing steadily\, providing more systems with precisely measured masses and radii and opening new opportunities to study how these objects form and evolve. In this talk\, I will give a short introduction to transiting brown dwarfs\, how they are detected\, and how their known population has been expanding over time. I will then present TOI-2155 b\, a newly characterised transiting brown dwarf lying right at the hydrogen-burning mass limit. With a mass of 81 $M_J$ (Jupiter mass)\, it contributes an important new data point to the growing population of transiting brown dwarfs and helps us probe the structure\, cooling\, and formation pathways of objects near the low-mass star boundary.
URL:https://cassa.site/event/colloquium-12/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2025/06/redyan.webp
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20251201T113000
DTEND;TZID=UTC:20251201T130000
DTSTAMP:20260514T162652
CREATED:20251127T074540Z
LAST-MODIFIED:20251127T081702Z
UID:6803-1764588600-1764594000@cassa.site
SUMMARY:CASSA Colloquium 11: Catching a star: How modern astronomers find exciting phenomena
DESCRIPTION:Speaker (in person at IUB): Tonima Tasnim Ananna\, PhD\, Assistant Professor\, Department of Physics and Astronomy\, Wayne State University\, USA \nTitle: Catching a star: How modern astronomers find exciting phenomena \nAbstract: Modern astrophysics infers extreme phenomena from precise\, theory-driven signatures. In this talk\, we will explore the empirical case for the Big Bang—cosmic expansion\, light-element abundances\, and the cosmic microwave background—and why these lines of evidence make it the most plausible origin of the Universe. We will examine how kilometer-scale laser interferometers identify black hole mergers with LIGO\, and how next-generation detectors may let us peek closer to the Big Bang via gravitational waves. Finally\, we will explore how JWST pushes galaxy surveys into the first few hundred million years after the Big Bang.
URL:https://cassa.site/event/colloquium-11/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2025/04/ananna.webp
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20251120T180000
DTEND;TZID=UTC:20251120T193000
DTSTAMP:20260514T162652
CREATED:20251120T134604Z
LAST-MODIFIED:20251126T061318Z
UID:6122-1763661600-1763667000@cassa.site
SUMMARY:CASSA Colloquium 10: Probing galaxy evolution using massive early-type galaxies at intermediate redshift
DESCRIPTION:Speaker (online): Pritom Mozumdar\, Postdoctoral Researcher\, Department of Physics and Astronomy\, University of California\, Los Angeles\, USA. \nTitle: Probing galaxy evolution using massive early-type galaxies at intermediate redshift \nAbstract: Over the past 8 billion years (since redshift\, z ~ 1)\, the Universe – and the galaxies within it – have changed dramatically. Cosmological simulations suggest that massive early-type galaxies (ETGs)\, which are large\, old systems mostly made of stars\, have slowly transformed in their internal structure during this time. However\, observational evidence of these transformations at intermediate redshift ( z ~ 0.5) isn’t conclusive and sometimes even seems to disagree with what simulations predict. One major reason is the lack of statistically large sample of ETGs with high-quality data at intermediate redshifts. To fill this gap\, I assembled a sample of around 200 massive ETGs at 0.25 < z < 0.75. With this dataset\, I addressed two big questions – 1) Have the stars in these galaxies become more randomly moving\, that is\, have their motions become less ordered\, over cosmic time? 2) Has the overall distribution of mass\, including both stars and dark matter\, changed as the Universe aged? By comparing these galaxies to similar ones in today’s Universe (z ~ 0)\, I found evidence that both the stellar motions and the mass distributions have evolved – offering new clues about how massive galaxies grew and changed over cosmic history.
URL:https://cassa.site/event/colloquium-10/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2025/10/mozumdar.webp
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20251113T180000
DTEND;TZID=UTC:20251113T190000
DTSTAMP:20260514T162652
CREATED:20251113T150529Z
LAST-MODIFIED:20251126T061455Z
UID:5906-1763056800-1763060400@cassa.site
SUMMARY:CASSA Colloquium 9: Photometric Redshifts for Next-Generation Sky Surveys
DESCRIPTION:Speaker (online): Biprateep Dey\, PhD\, Postdoctoral Fellow\, Department of Statistical Sciences\, University of Toronto\, Canada. \nTitle: Photometric Redshifts for Next-Generation Sky Surveys \nAbstract: Knowing the distances to galaxies as measured by their cosmological redshift is crucial for studies of cosmology\, galaxy evolution\, and astronomical transients. The next generation of astronomical imaging surveys (like LSST\, Euclid\, and Roman Observatories) will all be critically dependent on estimates of galaxy redshifts from imaging data alone; the resulting measurements are called photometric redshifts or photo-z’s. Traditional photo-z estimation methods only use measures of total light received from a galaxy (colors and magnitudes) as inputs\, thereby\, throwing away the rich pixel-level information present in images. Moreover\, the uncertainty estimates produced by these methods are not statistically well defined and the availability of data to train these methods is scarce. I will present my work on developing new deep learning-based photo-z estimation methods that take images directly as inputs and provide state-of-the-art photo-z prediction accuracy while being interpretable and requiring less training data. I will also talk about a statistical formalism that I developed to produce well-calibrated photo-z uncertainty estimates that are method-agnostic and employ minimal assumptions. Finally\, I will also provide an overview of our recent efforts to obtain spectroscopic samples to train for photo-z algorithms using the Dark Energy Spectroscopic Instrument (DESI).
URL:https://cassa.site/event/colloquium-9/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2025/10/dey.webp
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20250717T100000
DTEND;TZID=UTC:20250717T113000
DTSTAMP:20260514T162652
CREATED:20250717T065536Z
LAST-MODIFIED:20251126T061432Z
UID:5729-1752746400-1752751800@cassa.site
SUMMARY:CASSA Colloquium 8: Environmental variations of the low-mass IMF
DESCRIPTION:Speaker (online): Tabassum Shahriar Tanvir\, Postdoc Research Associate\, Department of Physics and Astronomy\, Iowa State University\, USA. \nTitle: Environmental variations of the low-mass IMF \nAbstract: The stellar initial mass function is arguably the most important distribution in astrophysics since it is at least partly determining everything from chemical evolution to the strength of stellar feedback during galaxy formation. While the IMF seems to be nearly universal in nearby\, Milky Way-like galaxies\, in recent years tentative evidence has emerged that the IMF varies slightly in the most extreme star-forming environments (e.g.: early-type galaxies). In a series of magnetohydrodynamic simulations including radiative and protostellar outflow feedback\, we study the environmental variation of the initial mass function. The simulations represent a carefully controlled experiment whereby we keep all dimensionless parameters of the flow constant except for feedback-related ones. We show that radiation feedback suppresses the formation of lower-mass objects more effectively as the surface density increases\, while protostellar outflows grow more effective at suppressing the formation of massive stars. The combined effect of these two trends is towards an IMF with a lower characteristic mass and a narrower overall mass range in high surface density environments. We further explore the effects of varying the metallicity\, and thus the dust properties\, of the star-forming gas. Dust matters because it is the crucial component of the gas that couples it to stellar radiation fields. We show that over a range in metallicity from 1% of Solar to 3x Solar\, corresponding to the lowest metallicity dwarf galaxies in the local universe to the most metal-rich early-types\, metallicity variations are much less important than variations in surface density in driving changes in the IMF. We therefore conclude that the higher surface densities and pressure found in early-type galaxies are most likely responsible for their anomalous IMFs\, while metallicity effects are negligible in comparison.
URL:https://cassa.site/event/colloquium-8/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/jpeg:https://cassa.site/wp-content/uploads/2025/06/tanvir-e1762452831598.jpeg
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20250626T120000
DTEND;TZID=UTC:20250626T140000
DTSTAMP:20260514T162652
CREATED:20250626T095039Z
LAST-MODIFIED:20251126T061415Z
UID:5477-1750939200-1750946400@cassa.site
SUMMARY:CASSA Colloquium 7: Strong Gravitational Lensing as a Probe of Cosmology
DESCRIPTION:Speaker (online): Kenneth C. Wong\, PhD\, Assistant Professor\, Research Center for the Early Universe (RESCEU)\, University of Tokyo\, Japan. \nAbstract: Strong gravitational lensing is sensitive to the total mass distribution along the line of sight\, making it a unique probe of dark matter in galaxies and clusters\, and useful for studying resolved properties of the magnified background sources. Strong lensing is also valuable for constraining cosmology through lensed quasars\, which can be monitored to measure the “time delay” between the multiple images and constrain the Hubble constant ($H_0$). This method of measuring $H_0$ is independent of type Ia supernovae and CMB observations\, and may shed light on the $H_0$ tension between local universe and CMB measurements. The latest results from the TDCOSMO project constrains $H_0$ to be $\sim 72$ km/s/Mpc in a flat Lambda CDM cosmology with a precision of $\sim 5\%$. This result is maximally conservative with respect to galaxy mass profiles\, and is consistent with independent determinations of $H_0$ using type Ia supernovae calibrated by the distance ladder method. To improve this measurement\, as well as leverage the power of strong lensing to study galaxy structure and magnified background sources\, we require deep wide-area imaging surveys to build up a statistical sample of lenses\, which in general are rare objects. The Hyper-Suprime Cam SSP is an optical survey using the Subaru Telescope that covers $>1000$ deg$^2$ of the sky to a depth of $r\sim 26$. The HSC SSP strong lensing working group is focused on searching for new lenses of all types and scales and using these systems for studies of galaxy structure and cosmology. We have developed a variety of lens search methods\, including recent machine learning techniques that can be applied to future datasets such as LSST and Euclid. \n\n\nTDCOSMO 2025 milestone paper: https://arxiv.org/abs/2506.03023 \n\n\nPapers relevant for the second part of the talk:\n\nhttps://ui.adsabs.harvard.edu/abs/2018PASJ…70S..29S/\nhttps://ui.adsabs.harvard.edu/abs/2018ApJ…867..107W/\nhttps://ui.adsabs.harvard.edu/abs/2020A%26A…636A..87C/\nhttps://ui.adsabs.harvard.edu/abs/2024MNRAS.535.1625J/
URL:https://cassa.site/event/colloquium-7/
LOCATION:CASSA\, IUB Main Building Rooftop\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA (Main Building Rooftop)\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cassa.site/wp-content/uploads/2025/06/kcw.png
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20250206T130000
DTEND;TZID=UTC:20250206T143000
DTSTAMP:20260514T162652
CREATED:20250206T114409Z
LAST-MODIFIED:20251126T061345Z
UID:4549-1738846800-1738852200@cassa.site
SUMMARY:CASSA Colloquium 6: Unraveling the distant Universe with wide-field surveys of star-forming galaxies
DESCRIPTION:Speaker: Tanveer Karim\, PhD\, Postdoctoral Fellow at the David A. Dunlap Department of Astronomy & Astrophysics\, University of Toronto\, and a member of the Dark Energy Spectroscopic Instrument (DESI) collaboration and the Dark Energy Science Collaboration (DESC). \nAbstract: Over the past decade\, cosmology has encountered significant tensions between different measurements of key cosmological parameters\, particularly when comparing the cosmic microwave background (CMB) with data from large-scale structures. Historically\, large-scale structure observations have primarily focused on the Universe below redshift 1 using galaxies that are 100-1000 times more massive than our Milky Way. However\, ongoing and upcoming surveys\, such as the Dark Energy Spectroscopic Instrument (DESI) and the Rubin Observatory\, are expanding these measurements beyond redshift 1\, opening new avenues for exploration. In this talk\, I will discuss the exciting opportunities and the challenges of probing the Universe at 𝑧 ≥ 1 using wide-field surveys of star-forming and less massive galaxies. I will present recent results from the cross-correlation of DESI Legacy Imaging Surveys’ Emission-Line Galaxies with Planck CMB lensing and contextualize reasons for various apparent tensions. \nGoogle Meet: https://meet.google.com/izz-qwux-pod
URL:https://cassa.site/event/colloquium-6/
LOCATION:Room MK5004\, DMK Building\, IUB\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara Ra\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2025/01/karim-e1740627757393.webp
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20250130T140000
DTEND;TZID=UTC:20250130T150000
DTSTAMP:20260514T162652
CREATED:20250130T092631Z
LAST-MODIFIED:20251126T061255Z
UID:3999-1738245600-1738249200@cassa.site
SUMMARY:CASSA Colloquium 5: Lower Dark Matter in the Local Group Galaxies and the Origin of the MW Dwarfs
DESCRIPTION:Speaker:\nIstiak Akib\, PhD candidate\, Laboratoire d’Instrumentation et de Recherche en Astrophysique (LIRA)\, Observatoire de Paris\, Paris Sciences et Lettres University (PSL). \n\nAbstract:\nFitting the flat rotation curves of the Galaxies indicate vast majority of the matter content in the galaxies is dark matter\, even higher than the cosmological estimate of 85% and giving rise to the missing baryon problem. However\, these rotation curve fits assume equilibrium conditions at the disk outskirts. This is not necessarily always fulfilled since on average galaxies have gone through a major merger 6 Gyr ago. For the MW\, the last major merger was 9-10 Gyr ago and the disk outskirts had enough time to reasonably fulfill the equilibrium conditions. Gaia DR3 rotation curve for the MW differs significantly from a flat fit and is consistent with a Keplerian decline. This gives a mass of $2.06\times 10^{11}$ M$_\odot$\, resulting in a dark matter fraction of 70%. Another estimate for the galaxy mass comes from comparing the time frame of the bulge formation and the accretion of the satellites with their binding energies. For the MW\, this is in agreement with the mass from the rotation curve. Andromeda Galaxy (M31) had a recent 2-3 Gyr major merger and hence the disk outskirts are likely not in equilibrium. Hydrodynamical modeling of this merger resulting in an M31 of mass $4.5\times 10^{11}$ M$_\odot$ and 68% dark matter reproduces the observational features of the M31 and especially its rotation curve. These M31 merger models indicate tidal tails coming towards the MW with significant stellar and gas particles. Part of these tails is found in agreement in the 6D space with most of the VPOS (Vast POlar Structure) satellites including the LMC for the case of such low mass MW models. This may explain the origin of the MW’s plane of satellites and is a first indication of matter exchange between these two galaxies. \nRelevant papers:\n\nJiao et al 2023: Detection of the Keplerian decline in the Milky Way rotation curve.\nHammer et al 2024a: The Milky Way accretion history compared to cosmological simulations.\nHammer et al 2024b: Dark matter fraction derived from the M31 rotation curve.\nAkib et al 2025: An intriguing coincidence between the majority of the VPOS dwarfs and a recent major merger at the M31 position (in revision at A&A).\nJiao et al 2025: Dark matter mass range in the Milky Way derived from the rotation curve (in preparation).
URL:https://cassa.site/event/colloquium-5/
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2024/12/akib-1.webp
ORGANIZER;CN="CASSA%2C Independent University%2C Bangladesh":MAILTO:cassa@iub.edu.bd
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20250109T130000
DTEND;TZID=UTC:20250109T140000
DTSTAMP:20260514T162652
CREATED:20250109T092216Z
LAST-MODIFIED:20250111T143857Z
UID:3768-1736427600-1736431200@cassa.site
SUMMARY:CASSA Colloquium 4: Astronomy in Space: Pioneering Missions for Lunar and Orbital Observatories
DESCRIPTION:Speaker: Shah Mohammad Bahauddin\, PhD\, Research Faculty\, Laboratory for Atmospheric and Space Physics (LASP)\, Astrophysical & Planetary Sciences Department\, University of Colorado\, Boulder\, USA. \nAbstract: The next frontier of astronomy lies in leveraging the unique environments of space and the Moon to unlock unprecedented scientific discoveries. This presentation will explore the speaker’s journey of transforming scientific questions into mission concepts\, focusing on the development of space and lunar observatories. Drawing on experience with NASA mission concepts\, the talk will emphasize the intersection of scientific motivation\, instrument design\, and mission planning. It will also highlight the transformative potential of innovative technologies\, such as advanced optical designs\, onboard artificial intelligence\, and cutting-edge signal processing techniques\, in enabling new avenues for space astronomy. By harnessing the unique advantages of space-based and lunar observatories\, these missions aim to address fundamental questions about the origins\, dynamics\, and evolution of the universe. \nRelevant article: This May Be the First Complete Observation of a Nanoflare\, NASA.
URL:https://cassa.site/event/colloquium-4/
LOCATION:Lecture Gallery MK9006\, DMK Building\, IUB\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2024/11/bahauddin-e1732621966981.webp
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20250105T130000
DTEND;TZID=UTC:20250105T140000
DTSTAMP:20260514T162652
CREATED:20250105T155404Z
LAST-MODIFIED:20250111T143847Z
UID:3813-1736082000-1736085600@cassa.site
SUMMARY:CASSA Colloquium 3: Measuring the Expansion Rate of the Universe from Carnegie Supernova Project
DESCRIPTION:Speaker: Syed A Uddin\, PhD\, Department of Physics and Astronomy\, University of South Carolina\, USA. \nThe Known Unknowns of Observational Cosmology: Measuring the Expansion Rate of the Universe from Carnegie Supernova Project \nAbstract: In the era of precision cosmology\, where percent-level accuracy in measurements is now within reach\, we are still confronted with profound enigmas: dark matter\, dark energy\, and the Universe’s dark ages. Compounding these challenges is the ongoing discrepancy in Hubble constant values\, known as the Hubble tension\, between measurements from the Cosmic Microwave Background and those based on the Type Ia Supernova distance scale. In this talk\, I will explore key milestones in observational cosmology\, delve into the intricacies of Hubble constant measurements\, and share our latest findings from the Carnegie Supernova Project. \nRelevant paper: Carnegie Supernova Project I and II: Measurements of H0 Using Cepheid\, Tip of the Red Giant Branch\, and Surface Brightness Fluctuation Distance Calibration to Type Ia Supernovae.
URL:https://cassa.site/event/colloquium-3/
LOCATION:Lecture Gallery MK9006\, DMK Building\, IUB\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/jpeg:https://cassa.site/wp-content/uploads/2024/11/uddin.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20241219T130000
DTEND;TZID=UTC:20241219T140000
DTSTAMP:20260514T162652
CREATED:20241219T053125Z
LAST-MODIFIED:20250111T143834Z
UID:3600-1734613200-1734616800@cassa.site
SUMMARY:CASSA Colloquium 2: Exploring the Co-Evolution of Star Clusters and Galaxies Since Cosmic Dawn with JWST
DESCRIPTION:Speaker:\nLamiya Ashraf Mowla\, PhD\, Assistant Professor\, Department of Physics and Astronomy\, Wellesley College\, USA. \nAbstract:\nThe most distant galaxies observed date back to when the Universe was only 5% of its current age\, with progenitors of galaxies like the Milky Way being about 10\,000 times less massive. Using JWST and the magnification provided by gravitational lensing\, these low-mass galaxies can be detected and studied in detail. In this work\, we present JWST observations of the “Firefly Sparkle\,” a strongly lensed galaxy at (z = 8.3) in the CANadian Unbiased Cluster Survey (CANUCS). This galaxy features massive star clusters cocooned in a diffuse arc\, showcasing characteristics of a young\, gas-rich galaxy in the early stages of formation. The unresolved clusters display exceptionally high surface densities\, surpassing those of Milky Way globular clusters and nearby young star clusters\, along with nebular-dominated spectra\, low metallicity\, high gas density\, and elevated electron temperatures\, suggesting a top-heavy initial mass function (IMF). These observations provide the first spectrophotometric view of a typical galaxy at Cosmic Dawn\, highlighting JWST’s capability to investigate the co-evolution of galaxies and star clusters. I will also discuss plans to expand this work using future JWST cluster observations\, aiming to deepen our understanding of the evolution of galaxy. \nRelevant reading:\n\nMowla et al. 2024\, “Formation of a low-mass galaxy from star clusters in a 600-million-year-old Universe\,” Nature.\nMowla et al. 2024\, “The Firefly Sparkle: The Earliest Stages of the Assembly of A Milky Way-type Galaxy in a 600 Myr Old Universe\,” submitted.\nওয়েবের দেখা গ্যালাক্সি ফায়ারফ্লাই স্পার্কল যেন এক ঝাঁক জোনাকি; কাসা নিউজ।\n\nDr. Mowla will give the talk in-person at IUB. The event is open to students and researchers of all universities both offline (at IUB) and online. If you RSVP and want to join online\, a google meet link will be shared with you before the event begins.
URL:https://cassa.site/event/colloquium-2/
LOCATION:Lecture Gallery MK9006\, DMK Building\, IUB\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/webp:https://cassa.site/wp-content/uploads/2024/11/mowla.webp
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=UTC:20241128T130000
DTEND;TZID=UTC:20241128T140000
DTSTAMP:20260514T162652
CREATED:20241128T052840Z
LAST-MODIFIED:20250111T143824Z
UID:3597-1732798800-1732802400@cassa.site
SUMMARY:CASSA Colloquium 1: Galaxy Evolution in High-Density Environments: Insights from Hydrodynamic Simulations and Multi-Wavelength Observations
DESCRIPTION:Speaker:\nSyeda Lammim Ahad\, PhD\, WCA Postdoctoral Fellow\, Waterloo Centre for Astrophysics\, University of Waterloo\, Canada; Associate Member\, CASSA. \nAbstract:\nGalaxies in the Universe are distributed along the intricate framework of the Cosmic Web. Groups and clusters of galaxies comprise the densest regions in this network and therefore\, are excellent cosmic laboratories to study different aspects of galaxy evolution in extreme environments. With the development of realistic cosmological hydrodynamic simulations\, we now have an excellent opportunity to study such galaxy evolution in extreme environments combining theory and observations. In this colloquium\, I will present the results from several studies exploring different properties of cluster galaxies and their host systems\, such as the spatial distribution of mass in galaxies within clusters\, the faint and diffuse stellar halo in groups and clusters\, and processes that quench star formation in massive galaxies in high-redshift clusters. I will discuss major questions\, current understanding\, and future research directions. Finally\, I will discuss the scope for conducting such research from Bangladesh\, illustrating the potential for local contributions to the global astrophysics community. \nRelevant reading:\n\n\nAhad et al.\, 2024\, An environment-dependent halo mass function as a driver for the early quenching of z ≥ 1.5 cluster galaxies\, MNRAS.\nAhad et al.\, 2023\, How to interpret measurements of diffuse light in stacked observations of groups and clusters of galaxies\, MNRAS.\nAhad et al.\, 2021\, The stellar mass function and evolution of the density profile of galaxy clusters from the Hydrangea simulations at 0 < z < 1.5\, MNRAS.\nআইইউবিতে গ্যালাক্সির বিবর্তন নিয়ে সৈয়দা লাম্‌মীম আহাদের সেমিনার\, বিজ্ঞানচিন্তা\, প্রথম আলো।\n\n\n 
URL:https://cassa.site/event/colloquium-1/
LOCATION:Lecture Gallery MK9006\, DMK Building\, IUB\, Plot 16\, Aftabuddin Ahmed Road\, Block B\, Bashundhara RA\, Dhaka\, 1229\, Bangladesh
CATEGORIES:Colloquium
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