Astrophysicist | Ex @UCPH_Research @mpi_astro @Stockholm_Uni @ObsStrasbourg @UnivofDelhi |
Copenhagen
Joined June 2015
- Tweets774
- Following106
- Followers507
- Likes480
Pinned Tweet
Discovery of two stellar structures in the orbit-metallicity space of our Galaxy. Shiva & Shakti appear to be two of those early, massive fragments that coalesced ~12 Gyr ago, forming the proto-Milky Way. Published in ApJ. arxiv.org/abs/2403.13051 @ESAGaia @APOGEEsurvey @mpi_astro
Milky Way’s Metal-Poor Stars display Chemical Transition near the Solar Radius. Accepted in ApJL. arxiv.org/abs/2508.08360
Results obtained using the data from @ESAGaia and @APOGEEsurvey .
Khyati Malhan retweeted
Today marks Gaia's end of observations: cosmos.esa.int/en/web/gaia/e…. Gaia now performs a set of technology tests to help future missions: cosmos.esa.int/en/web/gaia/t…. The most up to date view of our Milky Way was created thanks to Gaia, with much more to come with #GaiaDR4 + #GaiaDR5.
Our paper made it to the “Selections from 2024” series that looks back at some of the most-read AAS journal articles published in 2024!
Selections from 2024: Possible Proto-Galactic Fragments in the Milky Way
Two stellar structures discovered in the Milky Way this year may be fragments of proto-galaxies that formed before our galaxy was assembled. aasnova.org/2024/12/23/selec…
Khyati Malhan retweeted
In our new paper today (arxiv.org/abs/2407.20483), we report the catalog and photometry of the extragalactic tidal streams found in @theDESurvey as part of the Stellar Stream Legacy Survey. A comparison of the stream frequency with cosmological models is coming very soon!
A schematic overview of MW-mass satellite systems in Local group and beyond (taken from arxiv.org/pdf/2404.14498)
#dwarfgalaxies2024 conference in #Durham
The GD-1 stream surrounded by a "stellar cocoon" in the @desisurvey data!
By @monica_valluri et al.
The GD-1 stream shows clear evidence of a broader hotter “cocoon” in DESI Early Release data: arxiv.org/pdf/2407.06336! More data on the way.
Evolution of merger stars in the (Lz, E) space of a Milky Way analog in the TNG 50 cosmological simulation.
youtube.com/watch?v=qGNtSWwk…
The Gaia-Sausage/Enceladus stars, which were previously hypothesized to have originated from an ancient (8-11 Gyrs ago) merger event, likely came from a more recent (< 3 Gyrs ago) event, now dubbed as the Virgo Radial Merger (VRM).
📢 @ESAGaia reveals that the Milky Way’s last major collision was surprisingly recent!
Gaia unravels our history by studying the wrinkles created by collisions, but there's a catch. Like Benjamin Button, our galaxy is getting less wrinkly over time 👉 esa.int/Science_Exploration/…
ALT Artist impression of our galaxy from the side, split into two parts with a vertical white line. The line runs through the centre of the image where stars of our Milky Way take on a UFO shape. The UFO consists of a central bright orb surrounded by a slightly less bright disc. Thousands of small dots surround the UFO-shape, these are the stars in the Milky Way halo. The left part of the image shows these white dots clustered closer to the central UFO with some density variations. The right part of the image has the white dots spread out uniformly across a larger halo. In the background tens of stars pop out as bright white dots with plus-shaped diffraction spikes.
Khyati Malhan retweeted
Paper day! A central result from our survey of the Milky Way's outskirts:
"All-Sky Kinematics of the Distant Halo: The Reflex Response to the LMC"
arxiv.org/abs/2406.01676
Khyati Malhan retweeted
Paper thread!! This was up on arXiv a bit over a week ago: arxiv.org/abs/2405.13124
We show here the dynamical analysis of the first spectroscopic follow-up of extremely metal-poor stars using photometric metallicities based on Gaia XP CaHK magnitudes run on Pristine survey model
Khyati Malhan retweeted
What stellar substructures does Gaia map? This visualisation of the Milky Way by @StefanPWinc / @kmalhan07 highlights globular clusters, dwarf galaxies and stellar streams. Notice also Shakti & Shiva, subjects of a recent story:
esa.int/Science_Exploration/…
youtu.be/YQDfdpT6yZ4
Khyati Malhan retweeted
The paper I have been working on for a while is out! In this one I predicted the detectability of Globular Clusters in the full 6-year Euclid survey! And then tested detection models and size measurement using the first ERO data on the Fornax Cluster!
arxiv.org/abs/2405.14015
Khyati Malhan retweeted
Paper day: arxiv.org/abs/2404.11604
We show that Gaia BH3 is part of the ED-2 star cluster. The update astrometry puts GaiaBH3 in excellent agreement with the orbit of ED-2. Using some @ESO data we got last period we also show that ED-2 is very likely a disrupted globular cluster
Khyati Malhan retweeted
Paper day! With @ViktorHJonsson looking at velocities of stars in the Milky Way's warp. We find that they just don't match the picture of a steadily precessing warp where we see it today. arxiv.org/abs/2405.09624
ALT Velocities of stars in the Milky Way's warp
A webinar I gave @Swinburne, hosted by Prof. Duncan A. Forbes, on "The LMS1 stellar stream: A very metal-poor fossil remnant of our Galaxy's formation".
youtube.com/watch?v=6mtrAz5l…
A talk I gave for the "@IAU_org Commission H1 - The Local Universe" seminar, on the topic "Atlas of Milky Way mergers created using the @ESAGaia dataset".
youtu.be/soabSPRFims?t=129
Khyati Malhan retweeted
Our paper on the discovery of five dwarf galaxies around the galaxy NGC 253, found by @GJDonatiello in the @desisurvey deep imaging, is available today in: arxiv.org/pdf/2405.03769. This result gives new insights on the presence of a satellite plane in this Sculptor group spiral.
Galactic map of #StellarStreams detected in the @ESAGaia dataset. Each star in the stream represents an actual Gaia source, color-coded by heliocentric distance (as computed by the STREAMFINDER algorithm): blue for nearer (~1 kpc) and red for distant (>~30 kpc).
Khyati Malhan retweeted
2/ Called BH3, the #BlackHole was discovered by @ESAGaia 🛰️ because it imposes an odd wobbling motion on the star orbiting it ⭐️⚫️
Ground-based telescopes, including ESO’s #VLT 🔭, then found its mass to be 33 times that of the Sun.
Artist’s animation of the system 👇
Khyati Malhan retweeted
169. A billion radial velocities: DR3 includes 33 million radial velocities. DR4, in 2025, should have 100 million. A recent study has derived 125 million (of much lower accuracy) from the low-res BP/RP spectra, with perhaps 1–2 billion in the future.
wix.to/nWiwd2f