NGC 4449

NGC 4449
A Hubble Space Telescope (HST) image of NGC 4449.
Observation data (J2000 epoch)
Constellation	Canes Venatici^[1]
Right ascension	12^h 28^m 11.9^s^[2]
Declination	+44° 05′ 40″^[2]
Redshift	207 ± 4 km/s^[2]
Distance	~12 Mly (~ 3.6 Mpc)^[2]
Type	IBm^[2]
Apparent dimensions (V)	6′.2 × 4′.4^[2]
Apparent magnitude (V)	10.0^[2]
Other designations
UGC 7592,^[2] PGC 40973,^[2] Caldwell 21

NGC 4449 (also known as Caldwell 21) is an irregular galaxy in the constellation Canes Venatici. It is located about 12 million light-years away, part of the M94 Group (the Canes Venatici I Group), a galaxy group relatively close to the Local Group containing the Milky Way.

Characteristics

This well-studied galaxy is similar in size and brightness, and often compared to, the Milky Way's satellite galaxy, the Large Magellanic Cloud (LMC).^[3] NGC 4449 has a general bar shape, also characteristic of the LMC, with scattered young blue star clusters.

Starburst galaxy

Unlike the Large Magellanic Cloud, however, NGC 4449 is considered a starburst galaxy due to its high rate of star formation (twice the one of the LMC)^[4] and includes several massive and young star clusters,^[5]^[6] one of them in the galaxy's center.^[7]

Near the bottom (of the Hubble photo) is the pinkish glow of atomic hydrogen gas, the telltale tracer of massive star forming regions.

NGC 4449 is surrounded by a large envelope of neutral hydrogen that extends over an area of 75 arc minutes (14 times larger than the optical diameter of the galaxy). The envelope shows distortions and irregularities likely caused by interactions with nearby galaxies.^[8]

Interactions with nearby galaxies are thought to have influenced star formation in NGC 4449 and, in fact, in 2012 two small galaxies have been discovered interacting with this galaxy: a very low surface brightness disrupted dwarf spheroidal with the same stellar mass as NGC 4449's halo but with a ratio of dark matter to stellar matter between 5 and 10 times that of NGC 4449^[9] and a highly flattened globular cluster with two tails of young stars that may be the nucleus of a gas-rich galaxy.^[10] Both satellites have apparently been disrupted by NGC 4449 and are now being absorbed by it.^[9]^[10]

External links

Astronomy Picture of the Day – May 3, 2007, 10 July 2007, and 25 February 2011

NGC 4449 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

References

↑ R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN 0-933346-51-4.
1 2 3 4 5 6 7 8 9 "NASA/IPAC Extragalactic Database". Results for NGC 4449. Retrieved 2007-07-13.
↑ Karachentsev, Igor D.; Karachentseva, Valentina E.; Huchtmeier, Walter K.; Makarov, Dmitry I. (2003). "A Catalog of Neighboring Galaxies". The Astronomical Journal 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
↑ Annibali, F.; Aloisi, A.; Mack, J.; Tosi, M.; et al. (2008). "Starbursts in the Local Universe: New Hubble Space Telescope Advanced Camera for Surveys Observations of the Irregular Galaxy NGC 4449". The Astronomical Journal 135 (5): 1900–1916. Bibcode:2008AJ....135.1900A. doi:10.1088/0004-6256/135/5/1900.
↑ Reines, Amy E.; Johnson, Kelsey E.; Goss, W. M. (2008). "Emerging Massive Star Clusters Revealed: High-Resolution Imaging of NGC 4449 from the Radio to the Ultraviolet". The Astronomical Journal 135 (6): 2222–2239. arXiv:0804.0005. Bibcode:2008AJ....135.2222R. doi:10.1088/0004-6256/135/6/2222.
↑ Larsen, Søren S.; Brodie, Jean P.; Hunter, Deidre A. (2004). "Dynamical Mass Estimates for Five Young Massive Stellar Clusters". The Astronomical Journal 128 (5): 2295–2305. arXiv:astro-ph/0407373. Bibcode:2004AJ....128.2295L. doi:10.1086/424538.
↑ Böker, Torsten; van der Marel, Roeland P.; Mazzuca, Lisa; Rix, Hans-Walter; et al. (2001). "A Young Stellar Cluster in the Nucleus of NGC 4449". The Astronomical Journal 121 (3): 1473–1481. arXiv:astro-ph/0010542. Bibcode:2001AJ....121.1473B. doi:10.1086/319415.
↑ Bajaja, E.; Huchtmeier, W. K.; Klein, U. (1994). "The extended HI halo in NGC 4449". Astronomy and Astrophysics 285: 385–388. Bibcode:1994A&A...285..385B.
1 2 Martínez-Delgado, David; Romanowsky, Aaron J.; Gabany, R. Jay; Annibali, Francesca; et al. (2012). "Dwarfs Gobbling Dwarfs: A Stellar Tidal Stream around NGC 4449 and Hierarchical Galaxy Formation on Small Scales". The Astrophysical Journal Letters 748 (2). arXiv:1112.2154. Bibcode:2012ApJ...748L..24M. doi:10.1088/2041-8205/748/2/L24.
1 2 Annibali, F.; Tosi, M.; Aloisi, A.; van der Marel, R. P.; et al. (2012). "Cluster 77 in NGC 4449: The Nucleus of a Satellite Galaxy Being Transformed into a Globular Cluster?". The Astrophysical Journal Letters 745 (1). arXiv:1111.5861. Bibcode:2012ApJ...745L...1A. doi:10.1088/2041-8205/745/1/L1.

Caldwell catalogue

List	C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 C22 C23 C24 C25 C26 C27 C28 C29 C30 C31 C32 C33 C34 C35 C36 C37 C38 C39 C40 C41 C42 C43 C44 C45 C46 C47 C48 C49 C50 C51 C52 C53 C54 C55 C56 C57 C58 C59 C60 C61 C62 C63 C64 C65 C66 C67 C68 C69 C70 C71 C72 C73 C74 C75 C76 C77 C78 C79 C80 C81 C82 C83 C84 C85 C86 C87 C88 C89 C90 C91 C92 C93 C94 C95 C96 C97 C98 C99 C100 C101 C102 C103 C104 C105 C106 C107 C108 C109

See also	Messier Catalogue Catalogue of Nebulae and Clusters of Stars New General Catalogue Index Catalogue Revised New General Catalogue Herschel 400 Catalogue

Book:Caldwell catalogue Category:Caldwell objects Portal:Astronomy Commons:Caldwell objects

New General Catalogue 4000 to 4499

NGC 4000 NGC 4001 NGC 4002 NGC 4003 NGC 4004 NGC 4005 NGC 4006 NGC 4007 NGC 4008 NGC 4009 NGC 4010 NGC 4011 NGC 4012 NGC 4013 NGC 4014 NGC 4015 NGC 4016 NGC 4017 NGC 4018 NGC 4019 NGC 4020 NGC 4021 NGC 4022 NGC 4023 NGC 4024 NGC 4025 NGC 4026 NGC 4027 NGC 4028 NGC 4029 NGC 4030 NGC 4031 NGC 4032 NGC 4033 NGC 4034 NGC 4035 NGC 4036 NGC 4037 NGC 4038 NGC 4039 NGC 4040 NGC 4041 NGC 4042 NGC 4043 NGC 4044 NGC 4045 NGC 4046 NGC 4047 NGC 4048 NGC 4049 NGC 4050 NGC 4051 NGC 4052 NGC 4053 NGC 4054 NGC 4055 NGC 4056 NGC 4057 NGC 4058 NGC 4059 NGC 4060 NGC 4061 NGC 4062 NGC 4063 NGC 4064 NGC 4065 NGC 4066 NGC 4067 NGC 4068 NGC 4069 NGC 4070 NGC 4071 NGC 4072 NGC 4073 NGC 4074 NGC 4075 NGC 4076 NGC 4077 NGC 4078 NGC 4079 NGC 4080 NGC 4081 NGC 4082 NGC 4083 NGC 4084 NGC 4085 NGC 4086 NGC 4087 NGC 4088 NGC 4089 NGC 4090 NGC 4091 NGC 4092 NGC 4093 NGC 4094 NGC 4095 NGC 4096 NGC 4097 NGC 4098 NGC 4099 NGC 4100 NGC 4101 NGC 4102 NGC 4103 NGC 4104 NGC 4105 NGC 4106 NGC 4107 NGC 4108 NGC 4109 NGC 4110 NGC 4111 NGC 4112 NGC 4113 NGC 4114 NGC 4115 NGC 4116 NGC 4117 NGC 4118 NGC 4119 NGC 4120 NGC 4121 NGC 4122 NGC 4123 NGC 4124 NGC 4125 NGC 4126 NGC 4127 NGC 4128 NGC 4129 NGC 4130 NGC 4131 NGC 4132 NGC 4133 NGC 4134 NGC 4135 NGC 4136 NGC 4137 NGC 4138 NGC 4139 NGC 4140 NGC 4141 NGC 4142 NGC 4143 NGC 4144 NGC 4145 NGC 4146 NGC 4147 NGC 4148 NGC 4149 NGC 4150 NGC 4151 NGC 4152 NGC 4153 NGC 4154 NGC 4155 NGC 4156 NGC 4157 NGC 4158 NGC 4159 NGC 4160 NGC 4161 NGC 4162 NGC 4163 NGC 4164 NGC 4165 NGC 4166 NGC 4167 NGC 4168 NGC 4169 NGC 4170 NGC 4171 NGC 4172 NGC 4173 NGC 4174 NGC 4175 NGC 4176 NGC 4177 NGC 4178 NGC 4179 NGC 4180 NGC 4181 NGC 4182 NGC 4183 NGC 4184 NGC 4185 NGC 4186 NGC 4187 NGC 4188 NGC 4189 NGC 4190 NGC 4191 NGC 4192 NGC 4193 NGC 4194 NGC 4195 NGC 4196 NGC 4197 NGC 4198 NGC 4199 NGC 4200 NGC 4201 NGC 4202 NGC 4203 NGC 4204 NGC 4205 NGC 4206 NGC 4207 NGC 4208 NGC 4209 NGC 4210 NGC 4211 NGC 4212 NGC 4213 NGC 4214 NGC 4215 NGC 4216 NGC 4217 NGC 4218 NGC 4219 NGC 4220 NGC 4221 NGC 4222 NGC 4223 NGC 4224 NGC 4225 NGC 4226 NGC 4227 NGC 4228 NGC 4229 NGC 4230 NGC 4231 NGC 4232 NGC 4233 NGC 4234 NGC 4235 NGC 4236 NGC 4237 NGC 4238 NGC 4239 NGC 4240 NGC 4241 NGC 4242 NGC 4243 NGC 4244 NGC 4245 NGC 4246 NGC 4247 NGC 4248 NGC 4249 NGC 4250 NGC 4251 NGC 4252 NGC 4253 NGC 4254 NGC 4255 NGC 4256 NGC 4257 NGC 4258 NGC 4259 NGC 4260 NGC 4261 NGC 4262 NGC 4263 NGC 4264 NGC 4265 NGC 4266 NGC 4267 NGC 4268 NGC 4269 NGC 4270 NGC 4271 NGC 4272 NGC 4273 NGC 4274 NGC 4275 NGC 4276 NGC 4277 NGC 4278 NGC 4279 NGC 4280 NGC 4281 NGC 4282 NGC 4283 NGC 4284 NGC 4285 NGC 4286 NGC 4287 NGC 4288 NGC 4289 NGC 4290 NGC 4291 NGC 4292 NGC 4293 NGC 4294 NGC 4295 NGC 4296 NGC 4297 NGC 4298 NGC 4299 NGC 4300 NGC 4301 NGC 4302 NGC 4303 NGC 4304 NGC 4305 NGC 4306 NGC 4307 NGC 4308 NGC 4309 NGC 4310 NGC 4311 NGC 4312 NGC 4313 NGC 4314 NGC 4315 NGC 4316 NGC 4317 NGC 4318 NGC 4319 NGC 4320 NGC 4321 NGC 4322 NGC 4323 NGC 4324 NGC 4325 NGC 4326 NGC 4327 NGC 4328 NGC 4329 NGC 4330 NGC 4331 NGC 4332 NGC 4333 NGC 4334 NGC 4335 NGC 4336 NGC 4337 NGC 4338 NGC 4339 NGC 4340 NGC 4341 NGC 4342 NGC 4343 NGC 4344 NGC 4345 NGC 4346 NGC 4347 NGC 4348 NGC 4349 NGC 4350 NGC 4351 NGC 4352 NGC 4353 NGC 4354 NGC 4355 NGC 4356 NGC 4357 NGC 4358 NGC 4359 NGC 4360 NGC 4361 NGC 4362 NGC 4363 NGC 4364 NGC 4365 NGC 4366 NGC 4367 NGC 4368 NGC 4369 NGC 4370 NGC 4371 NGC 4372 NGC 4373 NGC 4374 NGC 4375 NGC 4376 NGC 4377 NGC 4378 NGC 4379 NGC 4380 NGC 4381 NGC 4382 NGC 4383 NGC 4384 NGC 4385 NGC 4386 NGC 4387 NGC 4388 NGC 4389 NGC 4390 NGC 4391 NGC 4392 NGC 4393 NGC 4394 NGC 4395 NGC 4396 NGC 4397 NGC 4398 NGC 4399 NGC 4400 NGC 4401 NGC 4402 NGC 4403 NGC 4404 NGC 4405 NGC 4406 NGC 4407 NGC 4408 NGC 4409 NGC 4410 NGC 4411 NGC 4412 NGC 4413 NGC 4414 NGC 4415 NGC 4416 NGC 4417 NGC 4418 NGC 4419 NGC 4420 NGC 4421 NGC 4422 NGC 4423 NGC 4424 NGC 4425 NGC 4426 NGC 4427 NGC 4428 NGC 4429 NGC 4430 NGC 4431 NGC 4432 NGC 4433 NGC 4434 NGC 4435 NGC 4436 NGC 4437 NGC 4438 NGC 4439 NGC 4440 NGC 4441 NGC 4442 NGC 4443 NGC 4444 NGC 4445 NGC 4446 NGC 4447 NGC 4448 NGC 4449 NGC 4450 NGC 4451 NGC 4452 NGC 4453 NGC 4454 NGC 4455 NGC 4456 NGC 4457 NGC 4458 NGC 4459 NGC 4460 NGC 4461 NGC 4462 NGC 4463 NGC 4464 NGC 4465 NGC 4466 NGC 4467 NGC 4468 NGC 4469 NGC 4470 NGC 4471 NGC 4472 NGC 4473 NGC 4474 NGC 4475 NGC 4476 NGC 4477 NGC 4478 NGC 4479 NGC 4480 NGC 4481 NGC 4482 NGC 4483 NGC 4484 NGC 4485 NGC 4486 NGC 4487 NGC 4488 NGC 4489 NGC 4490 NGC 4491 NGC 4492 NGC 4493 NGC 4494 NGC 4495 NGC 4496 NGC 4497 NGC 4498 NGC 4499

Astronomical catalog List of NGC objects

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