PG 1553+113 multiwavelength SED

PG 1553+113 is a BL Lac object at redshift z = 0.360. Its MMDC SED has 17,388 points from 53 catalogues, with dated data from 1998–⁠2025. Download the SED as CSV.

Updated 29 October 2026.

Names and position

Also known as 1ES 1553+113, 1FGL J1555.7+1111, 1FLAT J155543.0+111124, 2FGL J1555.7+1111, 2FHL J1555.7+1111, 2WHSP J155543.0+111123, 3FGL J1555.7+1111, 3HSP J155543.1+111124, 5BZB J1555+1111, BZB J1555+1111, CRATES J155543+111127, PG 1553+11.

Class: BL Lac
Redshift: z = 0.360
Position (ICRS): RA 238.92935°, Dec 11.19010°
Galactic: l 21.909°, b 43.964°

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

The SED

Data: 17,388 points (8 upper limits) from 53 catalogues
Dated data: 1998–2025 (MJD 50849–60933)
Undated catalogue values: 245
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: 5,726 UVOT and 5,633 XRT
Largest catalogues (points): MMDCXRT_ORBIT (6,032), MMDCXRT (4,760), MMDCOUV (2,863), ZTF (1,689), OUSXB (675)

Data by band

All 7 bands have data. The X-ray band has the most points, 11,755 of 17,388; its largest catalogue is MMDCXRT_ORBIT with 6,032.

Band	Points	Catalogues	Dated data
radio	77	13	1998
microwave	21	6	2012–2018
infrared	2,547	11	2010–2025
optical	2,949	5	2005–2025
ultraviolet	1	1	undated
X-ray	11,755	12	2005–2025
γ-ray	38	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=238.92935, dec=11.1901, name="PG 1553+113")

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

Nearby sources

PKS 1551+130, 1.8° away
4C +10.45, 3.3° away
4C +14.60, 5.1° away
4C +05.64, 5.9° 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).