Dr. Deep Anand

@styrofoamplates.bsky.social

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some guy working on some telescope. views are my own and not those of my employer or the government or anyone else.

arxiv paragraph about the new interstellar comet that ends in “perhaps by technological design”
Photo of my Indiana Pacers tshirt (Indy, 0 for Haliburton)
Buddy hield cycle meme
Barrel aged imperial stout bottle
A new car tire with a large nail embedded in it
description of JWST program 5989: Principal Investigator: Joseph Jensen Title: The JWST SBF Coma Cluster Survey: Building an Alternative Precision Distance Ladder for Cosmology
Figure 5. Color magnitude diagrams for each of the ten galaxies presented in this paper. The CMDs for each of the two chips are combined and displayed for each target, and the total number of stars is displayed in the top left. Only stars between 0.50 ≤ F090W − F150W ≤ 1.75 mag were used for the determination of the TRGB, due to the downward sloping of the TRGB at high metallicities, and hence colors (Anand et al. 2024a).
F090W/F150W/F356W color image of the core and halo of Messier 89. The extended spatial coverage of NIRCam allows us to obtain imaging that covers a very large dynamic range of surface brightness, facilitating both SBF and TRGB measurements. A few pixels in the core of the galaxy were saturated and were manually fixed to create the color image.
JWST/NIRCam footprints of ten elliptical galaxies, overlaid on optical imaging from the sloan digital sky survey.
arxiv paper and abstract: The TRGB-SBF Project. II. Resolving the Virgo Cluster with JWST Gagandeep S. Anand, R. Brent Tully, Yotam Cohen, Edward J. Shaya, Dmitry I. Makarov, Lidia N. Makarova, Maksim I. Chazov, John P. Blakeslee, Michele Cantiello, Joseph B. Jensen, Ehsan Kourkchi, Gabriella Raimondo The Virgo Cluster is the nearest substantial cluster of galaxies to the Milky Way and a cornerstone of the extragalactic distance scale. Here, we present JWST/NIRCam observations that simultaneously cover the cores and halos of ten galaxies in and around the Virgo Cluster and are designed to perform simultaneous measurements of the tip of the red giant branch (TRGB) and surface brightness fluctuations (SBF). Seven of the targets are within the Virgo Cluster and where we are able to resolve some of the cluster's substructure, while an additional three provide important constraints on Virgo infall. The seven galaxies within Virgo itself all have SBF measurements from the Advanced Camera
HST Cepheid distance linearity assessed by comparing to all other indicators. The comparison is a linear fit µHST = slope × µother − offset between each method (non-SN) and HST Cepheids (relative to the distance of NGC 4258, 29.4 mag) with one additional offset term for including SNe (M0 B), a total of one linearity term and two offsets. The HST Cepheid linearity is measured to be 0.994 ± 0.010, in good agreement with unity. There is also no evidence of an offset (non-SN) relative to all other indicators, with HST Cepheids in good accord with the mean. In the inset we show the combined constraint out to 5σ confidence and compared to the region that would be necessary to produce an 0.18 mag mean bias between NGC 4258 and the mean HST SN Ia host, a range of 2.5 mag.
paper title and abstract: JWST Validates HST Distance Measurements: Selection of Supernova Subsample Explains Differences in JWST Estimates of Local H0 Adam G. Riess, Dan Scolnic, Gagandeep S. Anand, Louise Breuval, Stefano Casertano, Lucas M. Macri, Siyang Li, Wenlong Yuan, Caroline D. Huang, Saurabh Jha, Yukei S. Murakami, Rachael Beaton, Dillon Brout, Tianrui Wu, Graeme E. Addison, Charles Bennett, Richard I. Anderson, Alexei V. Filippenko, Anthony Carr JWST provides new opportunities to cross-check the HST Cepheid/SNeIa distance ladder, which yields the most precise local measure of H0. We analyze early JWST subsamples (~1/4 of the HST sample) from the SH0ES and CCHP groups, calibrated by a single anchor (N4258). We find HST Cepheid distances agree well (~1 sigma) with all 8 combinations of methods, samples, and telescopes: JWST Cepheids, TRGB, and JAGB by either group, plus HST TRGB and Miras. The comparisons explicitly include the measurement uncertainty of each method in N425
Detailed scatter plot showing incredible agreement between JAGB, TRGB, and Cepheid distance measures
detailed scatter plot showing incredible (<0.03 mag) agreement between Cepheids, JAGB, TRGB.
left-panel: color magnitude diagram for NGC 1559 taken with JWST data. there is a clear break, which corresponds to the tip of the red giant branch (brightest ascent of red giant stars) right-panel: luminosity function and edge detection measurement of the TRGB
scatter plot of 7 galaxies (plus anchor galaxy) comparing HST Cepheid and JWST TRGB distance moduli. they agree to within ~0.01 magnitudes, whereas the size of the Hubble Tension is ~0.17 magnitudes
RGB image of blue spiral galaxy NGC 3370 taken with JWST. a zoomed-in inset shows the (low) stellar density where the TRGB measurements for this paper are taken
details for Sean Li's talk today at AAS243. it is program 441.03, at 2:20 PM CT (for 10 minutes).
arxiv page for https://arxiv.org/abs/2401.04777
period luminosity relations for 6 nearby galaxies with JWST. the reduction in scatter when compared to HST is greater than a factor of 2.5x.
comparison between two scenes centered on cepheid variables with both HST and JWST. the JWST imaging is drastically clearer.
arxiv page for https://arxiv.org/abs/2401.04773
nice color magnitude diagram for NGC 5584, supernova Ia host at 23 Mpc, and with a clear TRGB measurement
deep color magnitude diagram for NGC 4258 taken with JWST and used to measure its tip of the red giant branch.
arxiv page for https://arxiv.org/abs/2401.04776
three color RGB image of 4 nearby spiral galaxies observed with JWST
abstract of arXiv article here: https://arxiv.org/abs/2307.15806