1ES 1101-232 multiwavelength SED

1ES 1101-232 is a BL Lac object at redshift z = 0.186. Its MMDC SED has 4,357 points from 40 catalogues, with dated data from 1997–⁠2025. Download the SED as CSV.

Updated 29 October 2026.

Names and position

Also known as 1FGL J1103.7-2329, 1FLAT J110337.6-232931, 1H 1100-230, 1OUNYU J110338-2329.5, 1RXS J110337.7-232931, 2WHSP J110337.6-232930, 3FGL J1103.5-2329, 3HSP J110337.6-232931, 4U 1057-21, 5BZB J1103-2329, BZB J1103-2329, CRATES J110340-232927, H 1101-232, SHBL J110337.6-232931.

Class: BL Lac
Redshift: z = 0.186
Position (ICRS): RA 165.90673°, Dec −23.49200°
Galactic: l 273.190°, b 33.079°

Other names and measurements: NED and SIMBAD within 5″ of this position.

The SED

Data: 4,357 points (25 upper limits) from 40 catalogues
Dated data: 1997–2025 (MJD 50452–60821)
Undated catalogue values: 123
Frequency range of detections: log ν = 7.9–26.2 [Hz] (radio, microwave, infrared, optical, ultraviolet, X-ray, γ-ray)
Swift measurements analysed by MMDC: 794 UVOT and 1,419 XRT
Largest catalogues (points): MMDCXRT (1,622), ASAS-SN (1,056), NEOWISE (586), MMDCOUV (305), ZTF (300)

Data by band

All 7 bands have data. The X-ray band has the most points, 1,776 of 4,357; its largest catalogue is MMDCXRT with 1,622.

Band	Points	Catalogues	Dated data
radio	30	6	undated
microwave	2	2	undated
infrared	836	7	2010–2024
optical	1,680	7	2005–2025
ultraviolet	2	1	undated
X-ray	1,776	12	1997–2024
γ-ray	31	5	undated

Get the data

The SED as CSV from the MMDC SED API (docs.mmdc.am).

In Python, with astro-mmdc:

from astro_mmdc import MMDC
sed = MMDC().sed.get(ra=165.90673, dec=-23.492, name="1ES 1101-232")

The interactive SED plot, with time filtering and modeling (needs JavaScript).

Nearby sources

PKS 1034-293, 8.5° away
PKS 1127-14, 10.7° away
PKS 1004-217, 13.2° away
PKS 1203-26, 14.4° away

Other BL Lac objects

How to cite

Sahakyan, N., Vardanyan, V., Giommi, P., et al. 2024, AJ, 168, 289, doi:10.3847/1538-3881/ad8231 (arXiv:2410.01207).