OHP/MISTRAL optical spectroscopic followup of NGC1275
ATel #17959; Christophe Adami (LAM/Pytheas/AMU), Emeric LeFloc'h (CEA/Irfu) report on behalf of a larger collaboration:
on 12 Aug 2026; 03:40 UT
Credential Certification: Christophe Adami (christophe.adami@lam.fr)
Following the recent alerts given in ATel#17937, #17943, #17955 and #17957 describing the exceptional bright state of NGC1275, we observed this galaxy using the T193cm telescope at Observatoire de Haute-Provence (France) with the MISTRAL spectro-imager.
We first made a 5 minutes image of NGC1275 in i'-band, starting at 20260812_002945UT. No new sources was visible as compared to the PanStarrs i-band image. We then made a 1h spectroscopic exposure (3x20min) on the core of NGC1275 (with a North-South orientation of the slit and an aperture of 2.5arcsec, similar to the seeing) starting at 20260812_0033UT and ending at 20260812_0135UT. We compared this spectrum with the public NED-available other spectra in the same wavelength range.
In a preliminar analysis, we detect the same strong emission lines as e.g. Oxygen and Balmer lines. A few more weak lines seem to appear (observed e.g. at 6502, 6527, 6534, 6540, 6740, 6918, 6972A) without being clearly identified to elements present in http://astronomy.nmsu.edu/drewski/tableofemissionlines.html.
The Hgamma emission line also appears broader in the MISTRAL data as compared to older spectra. The main difference, however, is the now stronger HBeta (stronger than e.g. [OIII]b), and a new large wing toward the blue part of the line extending over ~100A when we compare our spectrum more specifically with the NED 2009 public spectrum (TNG/LRS).
We encourage other optical observations to confirm these apparent changes.
We acknowledge the excellent support from Observatoire de Haute-Provence and in particular Yoann Larralde Erasun.
