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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 030418: Optical afterglow
  2. GRB 030418: Finder for afterglow candidate
  3. GRB 030418: Optical afterglow candidate
  4. GRB 030329 OT position
  5. GRB030329: Optical Observations
  6. OT GRB 030329: early UBVRcIc spectral evolution
  7. GRB030329, UBVRI polarimetry, R-polarization
  8. GRB 030329: SARA Optical Observations
  9. OT GRB 030329: early spectrum
  10. GRB030329: VR Photometry at TNG
  11. GRB030324: Candidate Optical Afterglow (Erratum)
  12. GRB030324: Candidate Optical Afterglow
  13. IPN triangulation of GRB030414 (small error box)
  14. GRB 030413: Optical Observations
  15. GRB 030329 Rc observations
  16. IPN triangulation of GRB030413 (small error box)
  17. IPN triangulation of GRB030410 (annulus)
  18. Superluminal motion in GRB 030329 (Correction)
  19. Superluminal motion in GRB 030329
  20. GRB 030329 and SN 2003dh
  21. GRB030329, optical position
  22. GRB 030329 VLBA Observations
  23. CORRECTION TO IPN TRIANGULATION OF GRB050403
  24. IPN triangulation of GRB030406 (small error box)
  25. IPN triangulation of GRB050403 (small error box)
  26. IPN triangulation of GRB030403 (annulus)
  27. GRB 030329: BVRI photometry at Asiago
  28. GRB 030329, light curve flattens
  29. GRB 030329: VLT V-band photometry
  30. If the SN/GRB connection confirmed
  31. GRB 030329: Supernova Confirmed
  32. GRB030329: RTT150 optical observations
  33. GRB030329: Near Infrared Observations at Gunma
  34. GRB030329: HET spectroscopic monitoring
  35. Kiso observation of the GRB030329 at April 6
  36. GRB 030329, color evolution
  37. GRB030328, UBVRcIc field photometry
  38. GRB030329: Optical observcations
  39. GRB030329: BV photographic observations
  40. GRB 030329 Optical observations
  41. GRB 030329, color evolution
  42. GRB 030329: possible color change
  43. GRB030329: RTT150 optical observations
  44. GRB 030329: Supernova Spectrum Emerging
  45. GRB030329: Kiso B and R band observations
  46. GRB030329: RTT150 optical observation
  47. GRB030329: More AAVSO VR obs
  48. GRB030328: R upper limit after 6 hours by MASTER
  49. GRB 030329: BV photographic observations
  50. GRB 030329: SARA Optical Observations
  51. GRB 030329: SARA Optical Observations
  52. GRB030329, fading resumes
  53. GRB 030329, BVRI photometry
  54. GRB030329: Optical observations
  55. SDSS 0.5m PT observations of GRB030329 (correction)
  56. SDSS 0.5m PT observations of GRB030329
  57. GRB 030329, Optical observations
  58. GRB 030329, nearby galaxies
  59. GRB030329, cessation of fading
  60. GRB030329: final R-band light curve by MASTER
  61. GRB030329 - more 15 GHz radio data
  62. GRB030329 Radio 23/43/90 GHz observations at Nobeyama
  63. GRB 030329: Sub-millimeter detection
  64. GRB 030329: SARA Optical Observations
  65. GRB 030329: SARA Optical Observations
  66. OT GRB light curves and SN predictions
  67. GRB030329, optical observation
  68. GRB030329, optical observation
  69. GRB030329, new UBVRcIc field photometry
  70. GRB 030329, light curve and SN prediction
  71. GRB030329: optical observations at Tokyo Tech
  72. GRB 030329: optical observations
  73. GRB030329: multiple re-brightening phases
  74. GRB 030329, BRI photometry
  75. GRB030328: Full Observation, X-ray Fading and Spectrum Measured
  76. GRB 030329 , SPM optical observations
  77. GRB030329: Optical observations at Teramo
  78. GRB 030329: Radio observations at GMRT
  79. GRB030329: more 15GHz observations
  80. Further AAVSO V,B,R observations of GRB030329
  81. GRB 030329: Additional Mt. Laguna Optical Observations
  82. GRB 030329: SARA Optical Observations
  83. GRB 030329: Observations with ANDICAM
  84. GRB030329: Optical observations
  85. GRB030329: further optical photometry and evidence for a light curve discontinuity
  86. GRB 030329: Correction to GCN 2056
  87. GRB 030329: fitting parameters and re-brightening
  88. GRB 030329: KAIT optical photometry
  89. GRB030329 Further RBO Optical Observations
  90. triangulation of GRB 030331 (single error box)
  91. GRB030329 - OT rebrightens
  92. GRB 030329: SARA Optical Observations
  93. AAVSO V & R observations of GRB030329
  94. IPN triangulation of GRB030331 (annulus)
  95. GRB 030329: optical observations
  96. IPN triangulation of GRB030329b (large error box)
  97. GRB 030329: beginning of the new fading phase in optical band
  98. GRB 030329, optical spectroscopy
  99. GRB 030329: fading X-ray afterglow with RXTE
  100. GRB 030329: optical photometry

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