HALOGAS: HI OBSERVATIONS AND MODELING OF THE NEARBY EDGE-ON SPIRAL GALAXY NGC 4244

作者：Zschaechner Laura K^*; Rand Richard J; Heald George H; Gentile Gianfranco; Kamphuis Peter

来源：Astrophysical Journal, 2011, 740(1): 35.

DOI：10.1088/0004-637X/740/1/35

• galaxies: halos
• galaxies: individual (NGC 4244)
• galaxies: ISM
• galaxies: kinematics and dynamics
• galaxies: spiral
• galaxies: structure

We present 21 cm observations and models of the H I kinematics and distribution of NGC 4244, a nearby edge-on Scd galaxy observed as part of the Westerbork HALOGAS (Hydrogen Accretion in LOcal GAlaxieS) survey. Our models give insight into the Hi kinematics and distribution with an emphasis on the potential existence of extraplanar gas as well as a negative gradient in rotational velocity with height above the plane of the disk (a lag). Our models yield strong evidence against a significantly extended halo and instead favor a warp component along the line of sight as an explanation for most of the observed thickening of the disk. Based on these models, we detect a lag of -9(-2)(+3) km s(-1) kpc(-1) in the approaching half and -9 +/- 2 km s(-1) kpc(-1) in the receding half. This lag decreases in magnitude to -5 +/- 2 km s(-1) kpc(-1) and -4 +/- 2 km s(-1) kpc(-1) near a radius of 10 kpc in the approaching and receding halves, respectively. Additionally, we detect several distinct morphological and kinematic features including a shell that is probably driven by star formation within the disk.

• 出版日期2011-10-10