{ "id": "epzd0tkmep", "slug": "snr-g034-6-00-5", "title": "SNR G034.6-00.5", "updated": "2026-10-25", "topic_path": [ { "id": "physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical" }, { "id": "physical.astronomy", "label": "Astronomy", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.astronomy" }, { "id": "physical.astronomy.stellar", "label": "Stars and galaxies", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.astronomy.stellar" }, { "id": "physical.astronomy.stellar.nebulae_interstellar_medium", "label": "Nebulae and the interstellar medium", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.astronomy.stellar.nebulae_interstellar_medium" }, { "id": "physical.astronomy.stellar.named_nebulae", "label": "Named nebulae", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.astronomy.stellar.named_nebulae" }, { "id": "physical.astronomy.stellar.named_nebulae.supernova_remnants", "label": "Supernova remnants", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.astronomy.stellar.named_nebulae.supernova_remnants" } ], "geo": [ { "id": "geo.nongeo.nodate.physical.astronomy.stellar.named_nebulae", "label": "Non-geographic · Not dated: Named nebulae", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.physical.astronomy.stellar.named_nebulae", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.nodate", "label": "Non-geographic · Not dated", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate" }, { "id": "geo.nongeo.nodate.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.physical" }, { "id": "geo.nongeo.nodate.physical.astronomy", "label": "Astronomy", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.physical.astronomy" }, { "id": "geo.nongeo.nodate.physical.astronomy.stellar", "label": "Stars and galaxies", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.physical.astronomy.stellar" }, { "id": "geo.nongeo.nodate.physical.astronomy.stellar.nebulae_interstellar_medium", "label": "Nebulae and the interstellar medium", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.physical.astronomy.stellar.nebulae_interstellar_medium" }, { "id": "geo.nongeo.nodate.physical.astronomy.stellar.named_nebulae", "label": "Named nebulae", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.nodate.physical.astronomy.stellar.named_nebulae" } ] } ], "excerpt": "SNR G034.6-00.5, also known as W44 or 3C 392, is a mixed-morphology supernova remnant in Aquila, discovered in 1958, with a radio shell, bright interior X-rays, and a pulsar.", "snippet": "SNR G034.6-00.5, also known as W44 or 3C 392, is a mixed-morphology supernova remnant in Aquila, discovered in 1958, with a radio shell, bright interior X-rays, and a pulsar.", "node": "physical.astronomy.stellar.named_nebulae.supernova_remnants", "markdown": "# SNR G034.6-00.5\n\n**SNR G034.6-00.5**, also known as **W44**, 3C 392, and CTB 60, is a supernova remnant listed in the Cambridge catalog as G34.7−0.4, which notes the object has been called G34.6−0.5.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) It lies in a dense molecular environment and has a mixed morphology, with a radio shell surrounding centrally concentrated thermal X-rays and a pulsar with an associated pulsar wind nebula within its boundary.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) The remnant has a flux density of 240 Jy at 1 GHz and a spectral index of 0.37, making it one of the brighter radio remnants in the [Galactic plane](https://www.edgepedia.org/galactic-plane).[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) Distance estimates span roughly 2 to 3 kpc, with H I absorption suggesting 3.0 kpc, optical absorption 2.1 or 2.7 kpc, and H2 emission 2.8 kpc.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n\n| Key fact | Detail |\n|---|---|\n| Designations | W44; SNR G034.6-00.5; 3C 392; CTB 60; the Cambridge catalog lists it as G34.7−0.4 and notes it has been called G34.6−0.5[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) |\n| Position | Right ascension 18h 56m 00s, declination +01° 22′[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) |\n| Angular size | 35 × 27 arcmin[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) |\n| Radio brightness | 240 Jy at 1 GHz; spectral index 0.37[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) |\n| Distance | H I absorption suggests 3.0 kpc; optical absorption 2.1 or 2.7 kpc; H2 emission 2.8 kpc[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) |\n| Morphology | Mixed type: radio shell, centrally concentrated thermal X-rays, pulsar wind nebula[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) |\n\n## Discovery and naming\n\nIts Galactic-coordinate name is written both G34.6−0.5 and G34.7−0.4 in different catalogs; the Cambridge Galactic supernova remnant catalog notes that the object \"has been called G34.6−0.5.\"[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n\n## Radio morphology\n\nIn the radio band W44 appears as an asymmetric, nearly elliptical bright shell. The Cambridge catalog describes the shell as distorted and brighter to the east, with a pulsar and associated nebula within it.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) Early mapping work traced the source at successively higher resolution: Molonglo observations at 408 MHz with 3 arcminute resolution measured a flux density of 299 Jy, Arecibo measurements gave 540 ± 187 Jy at 430 MHz, and later Parkes, Effelsberg, and other maps resolved the shell structure at 2.7, 4.9, and 5 GHz.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n\nThe integrated radio spectrum is relatively flat for a shell remnant, with a spectral index of 0.37 (flux density falling as frequency to a low power) and a flux density of 240 Jy at 1 GHz, making it one of the brighter radio remnants in the Galactic plane.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n\n## X-ray properties\n\nX-ray emission from W44 is centrally concentrated with a thermal spectrum, and includes a pulsar wind nebula around the remnant's pulsar.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) Early Einstein Observatory observations found that the X-ray emission appears to be anticorrelated with the radio emission, consistent with the interior-filled X-ray morphology, and noted increased low-energy absorption toward the dense molecular cloud associated with the remnant.[2](https://www.cambridge.org/core/services/aop-cambridge-core/content/view/753097D79923BB0A351E020BE0C002E9/S0074180900033994a.pdf/div-class-title-einstein-observations-of-the-snrs-ic443-w44-and-w49b-div.pdf)\n\n## Environment and pulsar\n\nA pulsar lies within the boundary of the remnant, with an associated nebula seen in radio and X-ray observations.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n\nDistance estimates from different methods span roughly 2 to 3 kpc: H I absorption suggests 3.0 kpc, optical absorption suggests 2.1 or 2.7 kpc, and H2 emission suggests 2.8 kpc.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html) At these distances the 35 × 27 arcmin shell corresponds to a remnant tens of light-years across.[1](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n\n## As a mixed-morphology remnant\n\nW44 belongs to the class of mixed-morphology supernova remnants, objects showing considerable overlap in their properties, in which a radio shell surrounds bright interior thermal X-rays.[3](https://seti.berkeley.edu/exotica/BL_Exotica_20E_Notes.pdf) This combination contrasts with the more common shell-type remnants, whose X-ray emission follows the radio limb brightening. The centrally filled thermal X-rays, radiative recombination continua, and molecular-cloud association shown by W44 are the characteristics that define this class.[3](https://seti.berkeley.edu/exotica/BL_Exotica_20E_Notes.pdf)\n\nThe remnant remains a target of ongoing observation: amateur radio-telescope groups have recorded it repeatedly, with observations on 5 and 8 December 2022 and again in 2023, and it appears as a calibrated source in modern survey catalogs such as GLOSTAR, which lists its extent as Galactic longitude 34.390 to 34.930 and latitude −0.760 to −0.093.[4](https://radiotelescopelavillette.wordpress.com/activite-en-2023/) • [5](https://elib.dlr.de/207140/2/aa49885-24.pdf)\n\n## References\n\n1. [G34.7-0.4 (W44), A Catalogue of Galactic Supernova Remnants, Mullard Radio Astronomy Observatory, Cambridge](https://www.mrao.cam.ac.uk/surveys/snrs/snrs.G34.7-0.4.html)\n2. [Einstein Observations of the SNRs IC 443, W44 and W49B](https://www.cambridge.org/core/services/aop-cambridge-core/content/view/753097D79923BB0A351E020BE0C002E9/S0074180900033994a.pdf/div-class-title-einstein-observations-of-the-snrs-ic443-w44-and-w49b-div.pdf)\n3. [Notes on type: mixed morphology supernova remnants, Berkeley SETI Research Center Exotica catalog](https://seti.berkeley.edu/exotica/BL_Exotica_20E_Notes.pdf)\n4. [Activité en 2023, Radiotélescope du Parc de La Villette](https://radiotelescopelavillette.wordpress.com/activite-en-2023/)\n5. [GLOSTAR: Radio Source Catalog IV, Astronomy & Astrophysics](https://elib.dlr.de/207140/2/aa49885-24.pdf)\n\n---\n*Topic: Encyclopedia › Physical world and mathematics › Astronomy › Stars and galaxies › Nebulae and the interstellar medium › Named nebulae › Supernova remnants*\n\n*Initially written Oct 15, 2026 · Edited: Oct 25, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/snr-g034-6-00-5", "markdown_url": "https://www.edgepedia.org/snr-g034-6-00-5.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"SNR G034.6-00.5\", Edgepedia (EdgeChat), https://www.edgepedia.org/snr-g034-6-00-5. Edgepedia Community License 1.0.", "credit_md": "\"[SNR G034.6-00.5](https://www.edgepedia.org/snr-g034-6-00-5)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/snr-g034-6-00-5](https://www.edgepedia.org/snr-g034-6-00-5). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"SNR G034.6-00.5\", Edgepedia (EdgeChat), https://www.edgepedia.org/snr-g034-6-00-5. Edgepedia Community License 1.0.", "speakable": "SNR G034.6-00.5, also known as W44 or 3C 392, is a mixed-morphology supernova remnant in Aquila, discovered in 1958, with a radio shell, bright interior X-rays, and a pulsar." }