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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. MASTER:optical observations GRB030416
  2. ROTSE-III prompt optical detections of GRB 030418
  3. GRB030418: Upper limits from recent and historical observations.
  4. GRB030418: Kiso near infrared observations
  5. GRB 030418: Optical afterglow
  6. GRB 030418: Finder for afterglow candidate
  7. GRB 030418: Optical afterglow candidate
  8. GRB 030329 OT position
  9. GRB030329: Optical Observations
  10. OT GRB 030329: early UBVRcIc spectral evolution
  11. GRB030329, UBVRI polarimetry, R-polarization
  12. GRB 030329: SARA Optical Observations
  13. OT GRB 030329: early spectrum
  14. GRB030329: VR Photometry at TNG
  15. GRB030324: Candidate Optical Afterglow (Erratum)
  16. GRB030324: Candidate Optical Afterglow
  17. IPN triangulation of GRB030414 (small error box)
  18. GRB 030413: Optical Observations
  19. GRB 030329 Rc observations
  20. IPN triangulation of GRB030413 (small error box)
  21. IPN triangulation of GRB030410 (annulus)
  22. Superluminal motion in GRB 030329 (Correction)
  23. Superluminal motion in GRB 030329
  24. GRB 030329 and SN 2003dh
  25. GRB030329, optical position
  26. GRB 030329 VLBA Observations
  27. CORRECTION TO IPN TRIANGULATION OF GRB050403
  28. IPN triangulation of GRB030406 (small error box)
  29. IPN triangulation of GRB050403 (small error box)
  30. IPN triangulation of GRB030403 (annulus)
  31. GRB 030329: BVRI photometry at Asiago
  32. GRB 030329, light curve flattens
  33. GRB 030329: VLT V-band photometry
  34. If the SN/GRB connection confirmed
  35. GRB 030329: Supernova Confirmed
  36. GRB030329: RTT150 optical observations
  37. GRB030329: Near Infrared Observations at Gunma
  38. GRB030329: HET spectroscopic monitoring
  39. Kiso observation of the GRB030329 at April 6
  40. GRB 030329, color evolution
  41. GRB030328, UBVRcIc field photometry
  42. GRB030329: Optical observcations
  43. GRB030329: BV photographic observations
  44. GRB 030329 Optical observations
  45. GRB 030329, color evolution
  46. GRB 030329: possible color change
  47. GRB030329: RTT150 optical observations
  48. GRB 030329: Supernova Spectrum Emerging
  49. GRB030329: Kiso B and R band observations
  50. GRB030329: RTT150 optical observation
  51. GRB030329: More AAVSO VR obs
  52. GRB030328: R upper limit after 6 hours by MASTER
  53. GRB 030329: BV photographic observations
  54. GRB 030329: SARA Optical Observations
  55. GRB 030329: SARA Optical Observations
  56. GRB030329, fading resumes
  57. GRB 030329, BVRI photometry
  58. GRB030329: Optical observations
  59. SDSS 0.5m PT observations of GRB030329 (correction)
  60. SDSS 0.5m PT observations of GRB030329
  61. GRB 030329, Optical observations
  62. GRB 030329, nearby galaxies
  63. GRB030329, cessation of fading
  64. GRB030329: final R-band light curve by MASTER
  65. GRB030329 - more 15 GHz radio data
  66. GRB030329 Radio 23/43/90 GHz observations at Nobeyama
  67. GRB 030329: Sub-millimeter detection
  68. GRB 030329: SARA Optical Observations
  69. GRB 030329: SARA Optical Observations
  70. OT GRB light curves and SN predictions
  71. GRB030329, optical observation
  72. GRB030329, optical observation
  73. GRB030329, new UBVRcIc field photometry
  74. GRB 030329, light curve and SN prediction
  75. GRB030329: optical observations at Tokyo Tech
  76. GRB 030329: optical observations
  77. GRB030329: multiple re-brightening phases
  78. GRB 030329, BRI photometry
  79. GRB030328: Full Observation, X-ray Fading and Spectrum Measured
  80. GRB 030329 , SPM optical observations
  81. GRB030329: Optical observations at Teramo
  82. GRB 030329: Radio observations at GMRT
  83. GRB030329: more 15GHz observations
  84. Further AAVSO V,B,R observations of GRB030329
  85. GRB 030329: Additional Mt. Laguna Optical Observations
  86. GRB 030329: SARA Optical Observations
  87. GRB 030329: Observations with ANDICAM
  88. GRB030329: Optical observations
  89. GRB030329: further optical photometry and evidence for a light curve discontinuity
  90. GRB 030329: Correction to GCN 2056
  91. GRB 030329: fitting parameters and re-brightening
  92. GRB 030329: KAIT optical photometry
  93. GRB030329 Further RBO Optical Observations
  94. triangulation of GRB 030331 (single error box)
  95. GRB030329 - OT rebrightens
  96. GRB 030329: SARA Optical Observations
  97. AAVSO V & R observations of GRB030329
  98. IPN triangulation of GRB030331 (annulus)
  99. GRB 030329: optical observations
  100. IPN triangulation of GRB030329b (large error box)

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