Mrk 501 multiwavelength SED

Names and position

Also known as 1FGL J1653.9+3945, 1FLAT J165352.2+394536, 1Jy 1652+398, 2FGL J1653.9+3945, 2FHL J1653.9+3945, 2WHSP J165352.2+394535, 3FGL J1653.9+3945, 3HSP J165352.2+394537, 5BZB J1653+3945, BZB J1653+3945, CRATES J165353+394541, Markarian 501, Mkn 501, ROXA J165352.2+394536.6, S41652+398, TXS 1652+398, WMAP36, WMAP5 J1642+3948.

• Class: BL Lac
• Redshift: z = 0.0349
• Position (ICRS): RA 253.46757°, Dec 39.76017°
• Galactic: l 63.600°, b 38.859°

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

The SED

• Data: 54,530 points (12 upper limits) from 55 catalogues
• Dated data: 1997–2025 (MJD 50545–60967)
• Undated catalogue values: 619
• Frequency range of detections: log ν = 7.9–26.8 [Hz] (radio, microwave, infrared, optical, ultraviolet, X-ray, γ-ray)
• Swift measurements analysed by MMDC: 7,776 UVOT and 18,850 XRT
• Largest catalogues (points): MMDCXRT_ORBIT (21,403), MMDCXRT (17,712), ZTF (4,425), ASAS-SN (4,326), MMDCOUV (3,888)

Data by band

All 7 bands have data. The X-ray band has the most points, 40,848 of 54,530; its largest catalogue is MMDCXRT_ORBIT with 21,403.

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=253.46757, dec=39.76017, name="Mrk 501")

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

Nearby sources

• B3 1659+399, 1.5° away
• 3C 345, 2.1° away
• 4C +38.41, 4.0° away
• B3 1708+433, 4.6° away

Other BL Lac objects

• B3 1615+412
• I Zw 187
• RBS 1555
• B2 1811+31
• 1ES 1533+535
• 4C +56.27

How to cite

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