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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"

8474 results found.

  1. MASTER: RXTE GRB040308 optical observation
  2. RXTE GRB040229 optical observation: no candidate
  3. GRB 040228 Optical observations
  4. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  5. GRB031203: Chandra Observations
  6. GRB040106: Second Epoch Optical Observations
  7. GRB 031220: Optical observations of Chandra X-ray sources
  8. GRB031220 : Optical Observation of Lulin Observatory
  9. GRB 031203 I-band monitoring
  10. GRB 2974 follow-up observations
  11. GRB 021203: A Normal GRB viewed far off axis?
  12. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  13. GRB 031111: Optical observations
  14. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  15. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  16. GRB030913: Subaru Optical Observations
  17. GRB030913, candidate afterglow observations
  18. GRB 030913, optical candidate
  19. GRB 030824: Candidate Follow-Up
  20. XRF030824: optical observations
  21. XRF030824: Palomar observations
  22. GRB 030824: Candidate Afterglow (or Variable/Flare Star?)
  23. RAPTOR observations of GRB030823
  24. Summary of recent IPN and HETE detections of SGR bursts
  25. GRB 021206 Optical Observations
  26. GRB030725: Optical observations
  27. XRF030723: Re-analysis of ROTSE-III early images
  28. GRB030725, optical transient observations
  29. XRF 030723: VLT spectra
  30. XRF030723: Palomar observations and proposed counterpart
  31. GRB030725 (=H2779): A Bright GRB Localized by HETE
  32. RXTE PCA Observations of SGR1806-20 Region
  33. GRB 021206, Radio afterglow candidate
  34. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  35. GRB 030519B: optical observations.
  36. GRB 030528: Optical observations at RIKEN
  37. GRB 030329: HST ACS Observations of the Host
  38. GRB030324: Further Observations of the Candidate Optical Afterglow
  39. GRB 030418: Second Epoch Optical Observations with Magellan
  40. GRB030429: RTT150 optical observations, a possible host galaxy
  41. GRB030329: RTT150 optical observations and upper limit for a host
  42. GRB 030429: IR photometry with IRSF/SIRIUS
  43. GRB030501: TAROT candidate afterglow present in archival images
  44. GRB 030501: TAROT possible candidate counterpart
  45. GRB 030429: confirmation of afterglow candidate
  46. GRB030429, possible optical counterpart
  47. GRB 030429: ROTSE-III observations
  48. GRB030329, SPM optical observations
  49. Optical Observations of GRB 030418 with Magellan
  50. GRB 030418: Optical afterglow
  51. GRB 030418: Finder for afterglow candidate
  52. GRB 030418: Optical afterglow candidate
  53. GRB030324: Candidate Optical Afterglow (Erratum)
  54. GRB030324: Candidate Optical Afterglow
  55. GRB030329: HET spectroscopic monitoring
  56. GRB 030329: precise position from Kyoto images
  57. GRB 030329: Optical afterglow fading
  58. GRB 030329 follow-up
  59. GRB 030329: Optical afterglow candidate
  60. GRB 030329: OT candidate
  61. GRB 030329: Optical afterglow candidate
  62. GRB 030328: Finding chart
  63. GRB 030328: Optical afterglow candidate
  64. GRB030324 optical observation
  65. GRB030131, BVRcIc field photometry
  66. GRB030324, optical observations
  67. GRB030324, optical observations
  68. GRB030323: V, R, I photometry
  69. VLT/FORS2 spectra of GRB 030323
  70. GRB030323, ROTSE-III detection of possible optical counterpart
  71. GRB030323, optical observations
  72. GRB030323, possible optical counterpart
  73. IPN upper limit to a GRB associated with SN2003L
  74. GRB 030227 optical afterglow
  75. GRB 030227: Confirmed Optical Afterglow (S1-A)
  76. GRB 030227: fading of candidate optical afterglow 'S1-A'
  77. GRB 030227, possible optical counterpart of XMM-Newton source
  78. GRB030227 - faint tentative OT candidate
  79. GRB 030226: Optical afterglow
  80. GRB030226: Candidate optical afterglow
  81. GRB: Non-Referencing of GCN Circulars.
  82. GRB 030131: marginal optical detection
  83. GRB030131: Candidate Optical Afterglow
  84. GRB 030131, optical observations
  85. GRB030131: Kiso optical limit for corrected position
  86. GRB030131: Optical limits for corrected position
  87. GRB 030131: afterglow candidate
  88. GRB 020819: afterglow candidate
  89. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  90. GRB030115 submm upper limit
  91. GRB 030115: Further IR observations with IRSF/SIRIUS
  92. Publicizing GRB Discoveries - A Message from NASA HQ
  93. GRB 030115: Radio detection of IR candidate
  94. GRB 030115: IR observations with IRSF/SIRIUS
  95. GRB030115: R-band counterpart of IR candidate
  96. GRB030115, afterglow candidate
  97. GRB 021211: R-band observations at late-time
  98. GRB 030115, no optical candidate
  99. GRB 030115, optical candidate
  100. GRB 021211: Probable Host and Underlying Supernova

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