Blazar SED builder: multiwavelength data from radio to γ-rays

Search a blazar by name or sky position, and MMDC builds its time-resolved spectral energy distribution (SED) and light curves from archival catalogues and new Swift and Fermi-LAT analyses.

About the SED builder

Enter a source name (Mrk 421, 3C 279, 4FGL J1104.4+3812) or equatorial coordinates in degrees. MMDC searches over 80 catalogues and databases around the position, adds optical light curves from ASAS-SN, ZTF and Pan-STARRS, infrared data from WISE/NEOWISE, and Swift UVOT, Swift XRT, NuSTAR and Fermi-LAT results analysed by the MMDC team. A position nobody has searched before takes a few minutes; one searched before opens at once.

• Input: a source name, or RA and Dec (ICRS, degrees).
• The SED: νFν against frequency with errors and upper limits, by catalogue, filtered to a time window if you want one.
• Light curves per band, and the SED epoch by epoch.
• Download: the points as CSV (frequency, νFν and its error, upper-limit flag, observation time in MJD and catalogue of each point).
• Modeling: open the SED in the modeling tool to compare or fit SSC, EIC and lepto-hadronic models.

Sources with a precomputed SED have pages of their own, listed by class on the list of source pages. The website guide is at docs.mmdc.am; scripts can use the Python SDK astro-mmdc.