Access tiers You can sign in and explore limited-access pages as a Citizen Scientist. For full data tools & exports, request Scientist access via ORCID (approved for users with LSST data rights).

Quasar Harmonic Explorer

Explore periodicity, coherence, and variability in AGN light curves from LSST DP1, processed with the QhX pipeline.

Sign in to explore
Credit: NASA's GSFC / Scott Noble; simulation data, d'Ascoli et al. (2018)

Welcome to the QhX Hub

Discover, visualize, and export Active Galactic Nuclei data. Use the tools below to get started or scroll to learn about scope, access policy, and data provenance.

Learn more
Status: online Updated:

Overview

This release provides a catalogue of AGN light‑curve periodicity signatures from the Vera C. Rubin Observatory – Legacy Survey of Space and Time Data Preview 1 (DP1), derived with the Quasar harmonic eXplorer (QhX, v0.2.1) pipeline. Quasars are identified via cross‑matches with external compilations (e.g., Milliquas, Quaia, SDSS, DESI, ZTF), enabling reliable AGN classification and ancillary redshift estimates. Entries include both rare reliable periodic candidates and more common non‑periodic cases, categorized into pseudo‑periodic, transiently coherent, and red‑noise–dominated behaviours.

Key capabilities

search

Search

Cone search, period and SNR filters, verdict/bucket filters, CSV/VOTable export.

table_chart

Browse

Tabular overview with deep‑links to object detail pages and band diagnostics.

analytics

Visualize

Interactive scatter with log axes, coloring by verdict/bucket, band quality overlays.

Verification criteria

  • Good band: amp_snr ≥ 1.5 and R² ≥ 0.10
  • Coherent band: good band with phase_lag_vs_ref ≤ 0.20 cycles
  • Reliable candidate: n_coherent ≥ 2
  • Medium candidate: n_good ≥ 1 but not reliable
  • Discarded candidate: otherwise

Access & approval

Everyone can sign in and explore the hub with Citizen Scientist access. Scientist access unlocks research tools (advanced search, CSV/VOTable export, TOPCAT/PyVO endpoints) and is approved only for users with LSST data rights (e.g., authorized Rubin/LSST collaborators) or by invitation from the QhX team.

  1. Sign in (Google or ORCID) to start as Citizen Scientist.
  2. To request Scientist access: sign in with ORCID (required) and submit your institution + institutional email + short use-case note.
  3. Admin review (we may contact you for clarification).
  4. Upon approval, your role is upgraded to Scientist and data tools are unlocked.
how_to_reg Sign Up

Sign-in options may include Google and ORCID.

Data provenance & citation

Please cite LSST DP1 and the QhX pipeline in publications. Object pages include citation snippets. When exporting, metadata headers retain provenance fields and processing tags.

  • Source survey: LSST DP1
  • Processing: QhX v0.2.1
  • Cross‑matches: Milliquas, Quaia, SDSS, DESI, ZTF

Export & integration

download

CSV & VOTable

Export selections with consistent column naming and units.

hub

TOPCAT / PyVO

Interoperate with VO tools; use exported VOTables or service endpoints (where enabled).

verified

Reproducibility

Provenance is preserved in headers; each export includes a build timestamp and parameter summary.

FAQ

Scientist access is intended for users with LSST data rights (e.g., authorized Rubin/LSST collaborators) or by invitation from the QhX team. Everyone can sign in as a Citizen Scientist to explore limited-access pages.

The landing page is public; detailed data and exports require an approved account and acceptance of the Terms of Use.

Use the citation block on object pages or the README provided in each export package. Include LSST DP1 and QhX version tags.

Quick links

Overview Key capabilities Access & approval Export & integration FAQ Contact Terms of Use

Contact

For questions about access, integrations, or data corrections, contact our admin team at agncatalogue.sersag@gmail.com.

Privacy Notice

We collect minimal account information for authentication and access control (e.g., name, email, affiliation). We use aggregated usage metrics for performance monitoring. No advertising or third‑party tracking is used.

Contact agncatalogue.sersag@gmail.com for data requests.