Johannes R. Eskilt
@johanres.bsky.social
Cosmologist - University of Oslo. Trying my best to figure out if cosmic birefringence is real or not.
2) You can't blame dust! LFI and WMAP has negligible amount of dust. And ACT measurements do not use the foreground to calibrate. Hence, dust EB will again have a small impact on the measured birefringence angle.
October 17, 2025 at 4:58 PM
2) You can't blame dust! LFI and WMAP has negligible amount of dust. And ACT measurements do not use the foreground to calibrate. Hence, dust EB will again have a small impact on the measured birefringence angle.
1) It is not just Planck HFI that favors a non-zero birefringence angle. Planck LFI, WMAP and ACT also increase the significance (all towards a positive value).
October 17, 2025 at 4:56 PM
1) It is not just Planck HFI that favors a non-zero birefringence angle. Planck LFI, WMAP and ACT also increase the significance (all towards a positive value).
He already gave a talk on the results! youtu.be/vvxSsnZivTQ?...
[APCTP Colloquium] Parity Violation in Cosmology | Prof. Eiichiro Komatsu
YouTube video by APCTP
youtu.be
September 20, 2025 at 1:11 PM
He already gave a talk on the results! youtu.be/vvxSsnZivTQ?...
Combining these results, we get 4.6 sigma. Getting close to 5 sigma!
Graph credit: E. Komatsu
Graph credit: E. Komatsu
September 20, 2025 at 12:18 PM
Combining these results, we get 4.6 sigma. Getting close to 5 sigma!
Graph credit: E. Komatsu
Graph credit: E. Komatsu
September 20, 2025 at 9:08 AM
Combining these results, we get 4.6 sigma. Getting close to 5 sigma!
Graph credit: E. Komatsu
Graph credit: E. Komatsu
With Planck+WMAP, we reached 3.6 sigma. If another CMB experiment with different systematics and people doing the analysis reaches the same significance, I won't just be excited, I'll actually believe cosmic birefringence is real. But I might just be young and naive 😅
March 18, 2025 at 8:01 PM
With Planck+WMAP, we reached 3.6 sigma. If another CMB experiment with different systematics and people doing the analysis reaches the same significance, I won't just be excited, I'll actually believe cosmic birefringence is real. But I might just be young and naive 😅
I would expect you to be more excited about their 2.5 sigma birefringence results! It's a bit hidden, but they find a birefringence angle of 0.20 \pm 0.08 deg (Eq 14 in act.princeton.edu/sites/g/file...). Very consistent with our Planck+WMAP results! arxiv.org/abs/2205.13962
act.princeton.edu
March 18, 2025 at 7:14 PM
I would expect you to be more excited about their 2.5 sigma birefringence results! It's a bit hidden, but they find a birefringence angle of 0.20 \pm 0.08 deg (Eq 14 in act.princeton.edu/sites/g/file...). Very consistent with our Planck+WMAP results! arxiv.org/abs/2205.13962