Mrk 421 multiwavelength SED

Names and position

Also known as 1FGL J1104.4+3812, 1FLAT J110427.3+381231, 2FGL J1104.4+3812, 2FHL J1104.4+3812, 2WHSP J110427.3+381230, 3FGL J1104.4+3812, 3HSP J110427.3+381231, 3HSP J110427.3+381232, 4FGL J1104.4+3812, 5BZB J1104+3812, BZB J1104+3812, CRATES J110428+381228, Markarian 421, Mkn 421, SHBL J110427.3+381231, TeV J1104+382, TXS 1101+384, UGC6132.

• Class: BL Lac
• Redshift: z = 0.03
• Fermi-LAT (4FGL): 4FGL J1104.4+3812
• Position (ICRS): RA 166.11381°, Dec 38.20883°
• Galactic: l 179.832°, b 65.031°

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

The SED

• Data: 68,739 points (41 upper limits) from 47 catalogues
• Dated data: 1997–2026 (MJD 50567–61079)
• Undated catalogue values: 180
• Frequency range of detections: log ν = 7.9–26.4 [Hz] (radio, microwave, infrared, optical, ultraviolet, X-ray, γ-ray)
• Swift measurements analysed by MMDC: 6,318 UVOT and 22,318 XRT
• Largest catalogues (points): MMDCXRT_ORBIT (30,656), MMDCXRT (21,319), ASAS-SN (6,696), MMDCOUV (3,159), MMDCNuX (3,014)

Data by band

All 7 bands have data. The X-ray band has the most points, 55,313 of 68,739; its largest catalogue is MMDCXRT_ORBIT with 30,656.

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=166.11381, dec=38.20883, name="Mrk 421")

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

See an AstroGenesis answer about Mrk 421

Nearby sources

• B3 1038+392, 4.5° away
• RBS 0970, 5.1° away
• S4 1030+41, 6.8° away
• S4 1144+40, 8.4° away

Other BL Lac objects

• RBS 1040
• B3 1009+427
• B3 1159+450
• 1E 1207.9+3945
• 1ES 1028+511
• 1H 1013+498

How to cite

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