The Physics of the Intersteller Medium

by Dyson, J. E.; Williams, D. A.

• ISBN13: 9780750303064
• ISBN10: 0750303069
• Edition: 2nd
• Format: Hardcover
• Copyright: 1997-09-01
• Publisher: Inst of Physics Pub Inc

Summary

Updated and revised, The Physics of the Interstellar Medium, Second Edition leads the advanced undergraduate through a wide range of disciplines related to the interstellar medium. The book covers the study of the interstellar medium, which incorporates a large range of physical processes on both large and small scales. With chapter introductions provided to aid learning as well as problems and simple models included throughout, this comprehensive overview is suitable for any student studying physics or astrophysics. Considerable progress has been made in the field over the last decade, making this up-to-date understanding of the interstellar medium particularly timely.

Table of Contents

Preface to the second edition	xi	(2)
Useful tables	xiii
1 Introduction	1	(7)
1.1 Galaxies and the Galaxy	1	(4)
1.2 Evidence for matter between the stars	5	(1)
1.3 Preview	6	(1)
1.4 Units	7	(1)
2 How we obtain information about the interstellar medium	8	(20)
2.1 Introduction	8	(1)
2.2 Spectral lines	8	(13)
2.2.1 Introduction	8	(1)
2.2.2 Line shapes	9	(3)
2.2.3 Measurement of absorption and emission lines	12	(4)
2.2.4 Carriers of interstellar lines	16	(5)
2.3 Continuum radiation	21	(3)
2.4 Interstellar extinction	24	(1)
2.5 Some regions identified: interstellar clouds	25	(3)
3 Microscopic processes in the interstellar medium	28	(16)
3.1 Introduction	28	(1)
3.2 Cooling of the interstellar gas	28	(4)
3.2.1 How do gas clouds cool?	28	(1)
3.2.2 Cooling by ions and atoms	29	(1)
3.2.3 Cooling by molecules	30	(2)
3.3 Heating of the interstellar gas	32	(3)
3.3.1 How are interstellar gases heated?	32	(1)
3.3.2 Heating by starlight	32	(1)
3.3.3 Heating by cosmic rays and X-rays	32	(3)
3.3.4 Grains as a heating mechanism?	35	(1)
3.4 Molecule formation	35	(9)
3.4.1 The formation of interstellar molecules: the problem	35	(2)
3.4.2 Ion-molecule and neutral exchange reactions	37	(2)
3.4.3 Reaction networks	39	(3)
3.4.4 Ion-molecule chemistry in dark clouds	42	(2)
4 Interstellar grains	44	(20)
4.1 Evidence for grains	44	(6)
4.1.1 Depletion of elements	44	(1)
4.1.2 Extinction	44	(3)
4.1.3 Polarization	47	(1)
4.1.4 Scattered light	48	(1)
4.1.5 Solid state spectral lines	49	(1)
4.1.6 Luminescence from grains	50	(1)
4.2 Optics of grains	50	(4)
4.2.1 Introduction	50	(2)
4.2.2 Application to the interstellar medium	52	(2)
4.3 Formation and destruction of grains	54	(2)
4.3.1 Formation	54	(1)
4.3.2 Destruction	55	(1)
4.4 Physical properties of grains	56	(3)
4.4.1 Temperature	56	(1)
4.4.2 Grain electric charge	57	(2)
4.5 Grains as heating or cooling agents in interstellar gases	59	(1)
4.6 Grains as sites of molecule formation	60	(4)
4.6.1 The rate of H(2) formation on grain surfaces	60	(1)
4.6.2 H(2) formation on grains	61	(1)
4.6.3 Grains as sites for ice deposition	62	(2)
5 Radiatively excited regions	64	(23)
5.1 Introduction	64	(1)
5.2 Nebulae of pure hydrogen	65	(8)
5.2.1 The structure of pure hydrogen nebulae	65	(1)
5.2.2 Basic physical processes	65	(1)
5.2.3 The particle temperatures	66	(1)
5.2.4 The recombination of protons and electrons	67	(1)
5.2.5 The ionization of hydrogen	68	(2)
5.2.6 The sizes of ionized regions	70	(1)
5.2.7 How sharp-edged are nebulae?	70	(2)
5.2.8 The temperature of a pure hydrogen nebula	72	(1)
5.3 Nebulae containing heavy elements	73	(6)
5.3.1 Forbidden lines	73	(2)
5.3.2 The excitation of forbidden lines	75	(2)
5.3.3 The distribution of ions of heavy elements in nebulae	77	(2)
5.4 Radio-frequency spectra of nebulae	79	(5)
5.4.1 The radio-frequency continuum of a nebula	80	(1)
5.4.2 Radio-frequency lines from a nebula	81	(3)
5.5 Determining the physical structure of nebulae	84	(3)
5.5.1 The determination of electron temperatures	84	(1)
5.5.2 The determination of electron densities	84	(3)
6 Introduction to gas dynamics	87	(25)
6.1 Basic equations from the conservation laws	87	(6)
6.1.1 Introduction	87	(1)
6.1.2 Conservation principles	87	(1)
6.1.3 Conservation of mass	88	(1)
6.1.4 Conservation of momentum	89	(3)
6.1.5 Conservation of energy	92	(1)
6.2 Sound waves and the propagation of disturbances in gases	93	(2)
6.3 Adiabatic shock waves and their properties	95	(9)
6.3.1 Shock waves	95	(2)
6.3.2 Properties of shock waves: the jump conditions	97	(2)
6.3.3 What the Rankine-Hugoniot conditions tell us	99	(3)
6.3.4 Density, pressure and temperature changes across a shock	102	(1)
6.3.5 Results in a fixed frame of reference	103	(1)
6.4 Radiating shock waves	104	(5)
6.4.1 Cooling processes in shock-excited gas	104	(2)
6.4.2 Cooling times and cooling distances behind shock waves	106	(1)
6.4.3 Isothermal shock waves	107	(2)
6.5 Shock waves with magnetic fields	109	(3)
7 Gas dynamical effects of massive stars on the interstellar medium	112	(29)
7.1 Expansion of nebulae	112	(10)
7.1.1 Introduction	112	(1)
7.1.2 A simple model for the expansion of a photoionized nebula	113	(1)
7.1.3 The velocity of the ionization front	113	(1)
7.1.4 The radius of the ionization front	114	(1)
7.1.5 Results of the model	115	(1)
7.1.6 The final stage of evolution of an ionized region	116	(1)
7.1.7 Assumptions concerning the intermediate stages of evolution of the ionized region	117	(2)
7.1.8 Intermediate evolution: the model	119	(1)
7.1.9 Does the Stromgren sphere reach pressure equilibrium?	120	(1)
7.1.10 Conversion efficiency for stellar UV to kinetic energy	121	(1)
7.2 The effects of the stellar winds of massive stars on the interstellar gas	122	(7)
7.2.1 Introduction	122	(1)
7.2.2 The impact of the stellar wind on the surrounding gas	123	(1)
7.2.3 The regions of the flow pattern	123	(2)
7.2.4 A simple model	125	(2)
7.2.5 Efficiency of conversion of wind kinetic energy to gas kinetic energy	127	(1)
7.2.6 Does the wind impact on ionized gas?	128	(1)
7.3 Supernova explosions and supernova remnants	129	(6)
7.3.1 Introduction	129	(1)
7.3.2 A simple model of the supernova explosion	130	(1)
7.3.3 Radius and expansion velocity of the supernova bubble: the energy-conserving phase	131	(1)
7.3.4 Radius and expansion velocity of the thin shell: the momentum-conserving phase	132	(1)
7.3.5 Numerical estimates	133	(1)
7.3.6 Efficiency of energy conversion	134	(1)
7.3.7 The very early stages of supernova remnant evolution	134	(1)
7.4 Consequences of supernovae for the interstellar medium of galaxies	135	(3)
7.4.1 Diffuse neutral clouds	135	(1)
7.4.2 The motion of diffuse clouds	136	(1)
7.4.3 The production of coronal gas	137	(1)
7.5 The effects of groups of massive stars on the interstellar medium of galaxies	138	(3)
8 Star formation and star forming regions	141	(15)
8.1 Introduction	141	(7)
8.1.1 The equilibrium of a single cloud	141	(2)
8.1.2 The collapse of an isolated gas cloud and spontaneous star formation	143	(3)
8.1.3 Induced star formation	146	(2)
8.2 Observational signatures of star forming activity	148	(8)
8.2.1 Infrared sources	148	(1)
8.2.2 Large scale flows in star forming regions	149	(1)
8.2.3 Dynamics of momentum driven flows	150	(2)
8.2.4 Bipolar flows	152	(1)
8.2.5 Herbig-Haro objects	152	(4)
Answers to problems	156	(5)
Index	161