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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').
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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 030329 Optical Observations
  2. GRB030328, optical observation
  3. GRB 030329, BVRI photometry
  4. GRB030429: Optical Observations
  5. GRB030501: TAROT candidate afterglow present in archival images
  6. GRB 030501: TAROT possible candidate counterpart
  7. IPN triangulation of GRB030501 (IBIS event; annulus)
  8. IPN triangulation of GRB030501B (annulus)
  9. GRB 030429: confirmation of afterglow candidate
  10. GRB030429, possible optical counterpart
  11. GRB030501 localized by INTEGRAL
  12. GRB030425: CrAO optical observation
  13. IPN triangulation of GRB030429 (annulus)
  14. IPN triangulation of GRB030428 (two large error boxes)
  15. GRB 030329 Oprical observations in Rozhen observatory
  16. GRB 030429: ROTSE-III observations
  17. GRB 030324: Radio Observations
  18. GRB030329 observed as a sudden ionospheric disturbance (SID)
  19. IPN triangulation of GRB030426 (annulus)
  20. SNeIa AS THE POSSIBLE PROGENITORS OF SHORT-DURATION GRBs.
  21. IPN triangulation of GRB030425 (single error box)
  22. GRB030329, SPM optical observations (Correction)
  23. GRB030329, SPM optical observations
  24. GRB 030329, the review of the sky area in plate archive (1950-1998)
  25. GRB 030329: Spectral Evolution of SN 2003dh
  26. Optical Observations of GRB 030418 with Magellan
  27. GRB 030329: optical spectropolarimetry at VLT
  28. IPN triangulation of GRB030422C (annulus)
  29. IPN triangulation of GRB030422B (annulus)
  30. GRB 030329: wide-field photograph by R. Tamura 1 hr after the burst
  31. GRB030329: optical polarization
  32. IPN triangulation of GRB030422 (two large error boxes)
  33. GRB 030329 3.5 and 6 cm radio observations at RTF-32 telescope
  34. GRB030329, optical observation
  35. IPN triangulation of GRB030421 (annulus)
  36. MASTER:optical observations GRB030418
  37. MASTER:optical observations probable GRB030414
  38. GRB030329: 444 AAVSO Measurements
  39. IPN triangulation of GRB030419 (annulus)
  40. MASTER:optical observations GRB030416
  41. ROTSE-III prompt optical detections of GRB 030418
  42. GRB030418: Upper limits from recent and historical observations.
  43. GRB030418: Kiso near infrared observations
  44. GRB 030418: Optical afterglow
  45. GRB 030418: Finder for afterglow candidate
  46. GRB 030418: Optical afterglow candidate
  47. GRB 030329 OT position
  48. GRB030329: Optical Observations
  49. OT GRB 030329: early UBVRcIc spectral evolution
  50. GRB030329, UBVRI polarimetry, R-polarization
  51. GRB 030329: SARA Optical Observations
  52. OT GRB 030329: early spectrum
  53. GRB030329: VR Photometry at TNG
  54. GRB030324: Candidate Optical Afterglow (Erratum)
  55. GRB030324: Candidate Optical Afterglow
  56. IPN triangulation of GRB030414 (small error box)
  57. GRB 030413: Optical Observations
  58. GRB 030329 Rc observations
  59. IPN triangulation of GRB030413 (small error box)
  60. IPN triangulation of GRB030410 (annulus)
  61. Superluminal motion in GRB 030329 (Correction)
  62. Superluminal motion in GRB 030329
  63. GRB 030329 and SN 2003dh
  64. GRB030329, optical position
  65. GRB 030329 VLBA Observations
  66. CORRECTION TO IPN TRIANGULATION OF GRB050403
  67. IPN triangulation of GRB030406 (small error box)
  68. IPN triangulation of GRB050403 (small error box)
  69. IPN triangulation of GRB030403 (annulus)
  70. GRB 030329: BVRI photometry at Asiago
  71. GRB 030329, light curve flattens
  72. GRB 030329: VLT V-band photometry
  73. If the SN/GRB connection confirmed
  74. GRB 030329: Supernova Confirmed
  75. GRB030329: RTT150 optical observations
  76. GRB030329: Near Infrared Observations at Gunma
  77. GRB030329: HET spectroscopic monitoring
  78. Kiso observation of the GRB030329 at April 6
  79. GRB 030329, color evolution
  80. GRB030328, UBVRcIc field photometry
  81. GRB030329: Optical observcations
  82. GRB030329: BV photographic observations
  83. GRB 030329 Optical observations
  84. GRB 030329, color evolution
  85. GRB 030329: possible color change
  86. GRB030329: RTT150 optical observations
  87. GRB 030329: Supernova Spectrum Emerging
  88. GRB030329: Kiso B and R band observations
  89. GRB030329: RTT150 optical observation
  90. GRB030329: More AAVSO VR obs
  91. GRB030328: R upper limit after 6 hours by MASTER
  92. GRB 030329: BV photographic observations
  93. GRB 030329: SARA Optical Observations
  94. GRB 030329: SARA Optical Observations
  95. GRB030329, fading resumes
  96. GRB 030329, BVRI photometry
  97. GRB030329: Optical observations
  98. SDSS 0.5m PT observations of GRB030329 (correction)
  99. SDSS 0.5m PT observations of GRB030329
  100. GRB 030329, Optical observations

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